Running a business as a sole trader gives you control over your income, expenses and working arrangements. However, managing your own taxes comes with responsibilities that are easy to overlook when you are busy serving customers and growing your business.
Unlike employees whose Income Tax is normally deducted through PAYE, sole traders generally calculate and report their business profits through HMRC’s Self Assessment system.
You need to understand which income to declare, what expenses you can claim, how National Insurance is calculated and when you must pay your tax bill.
The 2026/27 tax year also brings important changes to digital tax reporting as Making Tax Digital for Income Tax becomes mandatory for eligible sole traders.
Whether you are submitting your first tax return or reviewing your existing accounting arrangements, this Accfirm guide explains how Sole Trader Self Assessment works, with practical examples, relevant HMRC rules and a step-by-step filing process.
What is Sole Trader Self Assessment?
Sole Trader Self Assessment is the process of reporting your self-employment income, allowable business expenses and other relevant income to HMRC. You use your tax return to calculate your taxable profits and establish your Income Tax and National Insurance liabilities.
Self Assessment is not a separate tax. It is the system HMRC uses to collect information and assess certain personal tax liabilities.
A sole trader’s tax return may include income from several sources, such as self-employment, employment, property and investments.
The key distinction: Sole traders normally pay personal Income Tax on their taxable business profits, rather than Corporation Tax on company profits.
A limited company has separate Corporation Tax obligations. A company director who also operates an independent sole trader business may have both company-related and personal tax reporting responsibilities.
1. Who needs to complete a Sole Trader Self Assessment tax return?
You generally need to register for Self Assessment if your gross self-employment income exceeds £1,000 in a tax year. You may also need to register below this threshold if you have another reporting obligation or want to make voluntary National Insurance contributions.
The £1,000 threshold relates to gross trading income before deducting business expenses.
For example, a self-employed graphic designer who receives £8,000 from clients and incurs £3,000 in business expenses has gross trading income of £8,000 and a profit of £5,000.
The designer would normally need to register for Self Assessment, even if their taxable income falls below the Personal Allowance.
When is Self Assessment compulsory for a sole trader?
You will normally need to register if:
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Your gross trading income exceeds £1,000 during the tax year.
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You need to demonstrate your self-employed status for certain benefits, including Tax-Free Childcare.
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You need to register as a subcontractor under the Construction Industry Scheme (CIS).
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You need to make voluntary Class 2 National Insurance contributions for relevant benefit or State Pension purposes.
If HMRC has already issued a notice requiring you to submit a Self Assessment tax return, you must deal with that filing requirement even if your income is low.
Do you need to file Self Assessment if you earn less than £1,000?
You do not normally need to register for Self Assessment solely because of eligible trading income of £1,000 or less in a tax year.
The trading allowance can exempt qualifying gross trading income up to £1,000 from Income Tax. However, the exemption does not automatically remove other tax reporting obligations.
For example, a sole trader who also receives substantial rental income may still need to submit a Self Assessment return.
Can you be employed and self-employed at the same time?
Yes. You can work as an employee and operate a separate sole trader business.
Your employer generally deducts Income Tax and employee National Insurance through PAYE. You may need to report your additional self-employment income through Self Assessment.
Your employment income and taxable business profits are considered together when calculating your total Income Tax liability.
Example: Emma earns £32,000 from employment and makes £12,000 in taxable profit from freelance consultancy.
Emma’s employment and self-employment income must both be considered in her personal tax calculation. Her self-employment profits do not receive a completely separate Personal Allowance.
If Emma is also a limited company director, her personal tax return may need to include relevant salary, dividends, benefits and other taxable income received from the company.
2. When is the Sole Trader Self Assessment deadline for 2026/27?
The standard online Self Assessment filing deadline for the 2026/27 tax year is 31 January 2028. However, if you are completing your 2025/26 tax return during 2026, the online filing deadline is 31 January 2027.
The UK tax year runs from 6 April to 5 April. You normally submit your annual Self Assessment return after the relevant tax year has ended.
HMRC Self Assessment deadlines for 2025/26 and 2026/27
| Requirement | 2025/26 tax year | 2026/27 tax year |
|---|---|---|
| Tax year begins | 6 April 2025 | 6 April 2026 |
| Tax year ends | 5 April 2026 | 5 April 2027 |
| Standard registration deadline | 5 October 2026 | 5 October 2027 |
| Paper tax return deadline | 31 October 2026 | 31 October 2027 |
| Online tax return deadline | 31 January 2027 | 31 January 2028 |
| Balancing tax payment deadline | 31 January 2027 | 31 January 2028 |
| Second payment on account for the following tax year | 31 July 2027 | 31 July 2028 |
Source: HMRC’s standard Self Assessment filing and payment timetable.
Important: The 5 October deadline is the standard notification deadline for someone who needs to register and has not previously been required to submit a return. Existing Self Assessment taxpayers may have different notification requirements, and HMRC can specify different filing dates in particular circumstances.
Example: Your first Self Assessment tax return
Suppose you started working as a self-employed marketing consultant on 1 September 2026.
Your business earns £25,000 in gross income before the tax year ends on 5 April 2027.
Assuming you have no existing Self Assessment registration, you would normally need to register by 5 October 2027.
Your first online tax return would then be due by 31 January 2028, with your balancing tax payment due on the same date.
You do not need to wait until October 2027 to register. Registering early can give you more time to obtain your Unique Taxpayer Reference and organise your accounting records.
3. How do you register for Self Assessment as a sole trader?
To register, visit the official GOV.UK sole trader registration service, provide your personal and business details, and complete HMRC’s Self Assessment registration process.
HMRC will issue or confirm your Unique Taxpayer Reference (UTR), which identifies your personal Self Assessment tax record.
Step-by-step Self Assessment registration process
Official HMRC registration
Register as a sole trader through GOV.UK
You can complete the standard sole trader registration directly with HMRC without paying a registration fee.
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Check whether you need to register for Self Assessment and establish the date your business started trading.
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Open the official HMRC sole trader registration service and sign in using the applicable government sign-in process.
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Provide your personal details, National Insurance number, contact information and business details.
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Check your registration information before submitting the application.
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Receive or confirm your UTR and arrange access to the relevant Self Assessment services.
If you are already registered for Self Assessment for another reason, you still need to notify HMRC about your self-employment so that your business activity is recorded correctly.
For a detailed explanation of the registration process, read Accfirm’s How to Register as a Sole Trader With HMRC guide.
4. What documents do you need to complete a sole trader tax return?
Before completing your Self Assessment return, gather your business income records, expense receipts, National Insurance number, UTR and information about any other taxable income.
Preparing these documents in advance reduces the risk of missing income, overstating business expenses or submitting an incorrect return.
Self Assessment preparation checklist
Tick each item as you prepare your tax return.
Documents prepared
Keep your records organised throughout the year. You should not need to reconstruct an entire year’s income and expenses immediately before the filing deadline.
5. How do you calculate your sole trader taxable profit?
Your taxable trading profit is generally your business income minus allowable business expenses, adjusted for any relevant tax allowances, reliefs and accounting rules.
HMRC uses your reported profits to calculate the Income Tax and Class 4 National Insurance contributions payable, taking account of your wider tax circumstances.
Sole trader profit calculation
The basic calculation is:
Example: A self-employed consultant
| Description | Annual amount |
|---|---|
| Business turnover | £42,000 |
| Allowable business expenses | £8,000 |
| Trading profit | £34,000 |
The consultant’s trading profit is £34,000 before any further tax adjustments.
The £8,000 of allowable business expenses reduces the amount of trading income subject to tax.
However, you must use the correct tax treatment for each expense. Personal expenditure, disallowed costs and some capital purchases cannot automatically be deducted in full.
What is the difference between turnover and profit?
Turnover is the total income generated by your business before deducting business expenses.
Profit is the amount remaining after deducting allowable business costs and applying the relevant accounting adjustments.
For example, a sole trader with £60,000 in annual sales and £25,000 in allowable expenses has a trading profit of £35,000 before any further adjustments.
Turnover is particularly important when assessing VAT registration and Making Tax Digital requirements, while taxable profits are central to calculating personal Income Tax and Class 4 National Insurance.
Should sole traders use cash basis or traditional accounting?
Cash basis is generally the default accounting method for eligible sole traders.
Under cash basis, you normally record business income when you receive payment and expenses when you pay them.
Traditional accounting, also called accruals accounting, generally records income when earned and expenses when incurred, subject to the applicable accounting rules.
You can choose traditional accounting where permitted. More complex businesses, particularly those with significant stock or credit transactions, may find it appropriate.
Example: You send a customer an invoice for £2,000 in March 2027, but the customer pays in April 2027.
Under cash basis, the payment would generally be included in the 2027/28 tax year because you received it after 5 April 2027.
Under traditional accounting, the income would generally be recognised in the accounting period in which it was earned, subject to the relevant rules.
Choose the correct accounting method before preparing your trading profit calculation. Switching methods can require adjustments to prevent income or expenditure being counted twice or omitted.
6. What expenses can a sole trader claim on Self Assessment?
Sole traders can claim qualifying business expenses when calculating taxable trading profits. Common allowable expenses include office costs, business travel, insurance, professional fees, advertising and eligible home-working costs.
The general rule is that ordinary business expenses must be incurred wholly and exclusively for the purposes of the trade.
If an expense has both business and personal elements, only the allowable business proportion can normally be deducted.
Common allowable expenses for sole traders
| Expense category | Examples |
|---|---|
| Office and administration | Stationery, printing, postage and business software |
| Business premises | Office rent, utilities and relevant business rates |
| Marketing | Website hosting, online advertising and promotional materials |
| Professional fees | Qualifying accountancy, bookkeeping and legal fees |
| Insurance | Business insurance and professional indemnity cover |
| Travel | Eligible business journeys, parking and accommodation |
| Home-working costs | Allowable business proportion of household expenses or applicable simplified expenses |
| Staff costs | Qualifying employee wages and subcontractor costs |
| Goods for resale | Stock, raw materials and relevant production costs |
| Equipment | Eligible business purchases, subject to the applicable capital expenditure rules |
Not every expense within these categories automatically qualifies for relief.
For example, ordinary everyday clothing is not generally deductible simply because you wear it while working. However, qualifying protective clothing or uniforms may be allowable.
Similarly, your regular journey between home and a permanent workplace is normally treated differently from qualifying business travel.
Can you claim home-working expenses?
Yes. Sole traders working from home may be able to claim a reasonable business proportion of certain household expenses.
Potentially eligible costs include electricity, heating, internet usage and other relevant household expenditure.
The amount claimed must reflect the business use of your home and comply with the applicable tax rules.
Alternatively, you may qualify for simplified expenses, which allow certain costs to be calculated using HMRC’s flat-rate methods.
Can you claim the £1,000 trading allowance instead of business expenses?
Yes, if you qualify. You can generally choose to deduct the £1,000 trading allowance instead of claiming your actual business expenses against eligible trading income.
You cannot deduct both the trading allowance and actual expenses from the same qualifying trading income.
Example:
| Calculation method | Actual expenses | Trading allowance |
|---|---|---|
| Gross trading income | £8,000 | £8,000 |
| Deduction | £2,500 | £1,000 |
| Resulting trading profit | £5,500 | £7,000 |
In this example, deducting the actual allowable expenses produces a lower trading profit.
If the business had only £400 of actual expenses, the trading allowance could produce a lower taxable profit, provided the individual qualifies to use it.
The trading allowance cannot be used to create a trading loss.
For more detailed guidance, read Accfirm’s article on Allowable Expenses for Sole Traders.
7. How much Income Tax does a sole trader pay in 2026/27?
Sole traders pay Income Tax on their taxable business profits, taking account of other taxable income, allowances and reliefs.
For the 2026/27 tax year, the standard UK Personal Allowance is £12,570. This means an eligible individual can normally receive up to £12,570 of total taxable income before paying Income Tax.
Income Tax rates for sole traders in England, Wales and Northern Ireland
| Annual income band | Income Tax rate |
|---|---|
| Up to £12,570 | 0% |
| £12,571–£50,270 | 20% |
| £50,271–£125,140 | 40% |
| Over £125,140 | 45% |
These bands assume entitlement to the full standard Personal Allowance and show the ordinary 2026/27 rates for non-savings, non-dividend income.
The Personal Allowance is reduced by £1 for every £2 of adjusted net income above £100,000. It is fully withdrawn when adjusted net income reaches £125,140.
Scottish taxpayers have different Income Tax bands for earnings and self-employment profits. The Scottish system includes starter, basic, intermediate, higher, advanced and top rates.
Example: Sole trader Income Tax calculation for 2026/27
Suppose a self-employed consultant in England reports the following business results:
| Description | Amount |
|---|---|
| Annual turnover | £35,000 |
| Allowable business expenses | £5,000 |
| Taxable trading profit | £30,000 |
| Standard Personal Allowance | £12,570 |
| Income subject to basic-rate tax | £17,430 |
Assume the consultant has no other taxable income, is entitled to the full Personal Allowance and has no additional reliefs or adjustments.
The Income Tax calculation is:
The consultant’s estimated Income Tax liability is £3,486.
National Insurance is calculated separately.
8. How is National Insurance calculated for sole traders in 2026/27?
Sole traders may pay Class 4 National Insurance based on their annual taxable trading profits.
For 2026/27, the main Class 4 rate is 6% on profits above £12,570 up to £50,270, and 2% on profits above £50,270.
Self-employed National Insurance rates for 2026/27
| National Insurance category | Rate or threshold |
|---|---|
| Class 4: profits up to £12,570 | 0% |
| Class 4: profits above £12,570 up to £50,270 | 6% |
| Class 4: profits above £50,270 | 2% |
| Class 2 Small Profits Threshold | £7,105 |
| Voluntary Class 2 rate, where eligible | £3.65 per week |
Most self-employed individuals no longer need to pay compulsory Class 2 National Insurance contributions.
Where qualifying profits reach the relevant threshold, Class 2 contributions are generally treated as paid for eligible benefit and State Pension purposes.
Individuals with profits below the Small Profits Threshold may be able to make voluntary Class 2 contributions to protect their National Insurance record.
Example: Income Tax and National Insurance on £30,000 profit
Using the same self-employed consultant from the previous example:
| Tax calculation | Amount |
|---|---|
| Taxable trading profit | £30,000.00 |
| Income Tax | £3,486.00 |
| Class 4 National Insurance | £1,045.80 |
| Total Income Tax and Class 4 NI | £4,531.80 |
The Class 4 National Insurance calculation is:
The consultant’s estimated Income Tax and Class 4 National Insurance liability for 2026/27 is therefore £4,531.80.
This illustration excludes other taxable income, adjustments, reliefs, tax already paid and payments on account.
It also excludes any student loan repayments or other relevant liabilities.
Accfirm tip: The amount of tax due on your Self Assessment statement may be higher than the tax calculated for one year because HMRC can also request payments on account towards the following year’s liability.
9. How to complete a Sole Trader Self Assessment tax return: Step-by-step
To complete your Sole Trader Self Assessment return, sign in to the appropriate HMRC service, select the relevant tax year, declare your income, enter your allowable expenses, check your tax calculation and submit the completed return.
The following steps describe the standard online Self Assessment process.
If you are required to use Making Tax Digital for Income Tax, you must follow the applicable digital reporting and compatible software process instead.
Step 1: Sign in to your HMRC Self Assessment account
Visit the official Self Assessment tax return service .
Sign in using the applicable government sign-in service and access your Self Assessment account.
Make sure your personal details are correct and select the tax year you need to complete.
For example, if you are submitting your tax return in September 2026, you may be completing the 2025/26 return, covering income from 6 April 2025 to 5 April 2026.
Step 2: Choose the relevant income sections
HMRC will ask questions about your income and circumstances to determine which sections of your tax return you need to complete.
You should provide accurate information about all relevant sources of taxable income.
For example, you may need to complete sections covering:
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Self-employment income.
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Employment income and PAYE tax already deducted.
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Property income.
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Dividends, savings interest and other investment income.
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Relevant pension income.
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Capital gains, where reportable.
HMRC’s standard individual tax return is the SA100. Self-employment income is reported using the appropriate self-employment supplementary pages.
SA103S is the short self-employment form, while SA103F is the full self-employment form used where more detailed reporting is required.
When filing online, the service or tax software generally guides you through the relevant sections rather than requiring you to complete every paper form separately.
Step 3: Enter your sole trader business information
Provide the information requested about your business.
Depending on your circumstances, this may include your business name, business description, trading start date and accounting period.
You will also need to confirm or provide relevant information about your accounting method.
Check that the business details match your records and that you are reporting income for the correct tax year.
If you operate more than one sole trader business, ensure the activities are reported correctly rather than automatically combining unrelated trades into one business.
Step 4: Declare your business turnover and income
Enter your total reportable business income for the relevant period.
Depending on your activities, income may include customer payments, consultancy fees, product sales and other receipts connected with your business.
The correct treatment of each receipt depends on the applicable tax and accounting rules.
Avoid reporting only the amount remaining in your business bank account.
Your bank balance is not the same as business turnover or taxable profit.
Step 5: Enter your allowable business expenses
Use your accounting records to identify and enter qualifying business expenses in the appropriate categories.
Your tax return should reflect the correct treatment of business expenditure, including any relevant adjustments for private use or capital purchases.
For example, if 60% of a mobile phone’s eligible usage relates to business activities, only the appropriate business proportion of the cost should normally be claimed.
Do not include personal expenditure or incorrectly deduct loan repayments, owner’s drawings or other non-allowable payments.
Step 6: Enter other taxable income and claim relevant reliefs
Add any additional reportable income and provide the information needed for applicable deductions and reliefs.
This might include employment earnings, pension contributions, Gift Aid donations or other items relevant to your personal tax position.
If you are employed as well as self-employed, check that the PAYE income and tax deducted are correctly included.
Company directors should also check whether relevant company salary, dividends and taxable benefits need to be reported.
Step 7: Review your Self Assessment tax calculation
Before submitting your return, review HMRC’s calculation of your Income Tax, National Insurance and other relevant liabilities.
Compare the reported figures with your accounting records.
Check whether previous payments, PAYE deductions, reliefs and payments on account have been reflected correctly.
If the result differs significantly from your expectations, investigate the difference before submitting the return.
Step 8: Submit your tax return and save your confirmation
Once you are satisfied that your return is complete and accurate, submit it through the appropriate HMRC service.
Save a copy of the completed return, tax calculation and submission acknowledgement.
You should also check your Self Assessment statement to establish how much tax you need to pay and when the payment is due.
Important: Submitting your tax return and paying your tax bill are separate actions. Filing a return before the deadline does not remove the obligation to pay the tax due on time.
10. How do payments on account work for sole traders?
Payments on account are advance payments towards your next Self Assessment tax bill. If they are required, HMRC normally asks you to make two instalments, each based on half of the relevant previous year’s liability.
The payment dates are 31 January and 31 July.
Payments on account generally include Income Tax and Class 4 National Insurance, but not every liability included in your Self Assessment calculation is necessarily part of the payments-on-account calculation.
When must you make payments on account?
Payments on account are normally required unless either:
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Your previous year’s relevant Self Assessment liability was less than £1,000.
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More than 80% of your previous year’s tax liability was paid outside Self Assessment, such as through PAYE.
HMRC uses your Self Assessment calculation to establish whether payments on account apply.
Example: Why your first Self Assessment payment may be higher than expected
Suppose your Income Tax and Class 4 National Insurance liability for 2026/27 is £4,000.
Assume you have not previously made any payments on account and that the full £4,000 is included in the payments-on-account calculation.
Your payments could be:
| Payment | Amount | Deadline |
|---|---|---|
| 2026/27 balancing payment | £4,000 | 31 January 2028 |
| First payment on account for 2027/28 | £2,000 | 31 January 2028 |
| Second payment on account for 2027/28 | £2,000 | 31 July 2028 |
| Total payable on 31 January 2028 | £6,000 | 31 January 2028 |
Your first January payment could therefore be £6,000, even though your calculated tax liability for 2026/27 is £4,000.
The additional £2,000 is an advance payment towards the next tax year, not an additional tax on your 2026/27 profits.
Can you reduce your payments on account?
You can ask HMRC to reduce your payments on account if you reasonably expect your next year’s tax liability to be lower.
For example, you may expect lower profits because you have reduced your working hours, lost a major customer or stopped trading.
However, reducing payments without a reasonable basis can result in interest being charged if the payments prove insufficient.
Review your expected annual profits before requesting a reduction.
11. How do you pay your Sole Trader Self Assessment tax bill?
You can pay your Self Assessment tax bill through the official HMRC payment service using an available payment method, including online banking, debit card or Direct Debit.
HMRC also allows taxpayers to make advance payments towards their bills.
Pay your Self Assessment tax bill
Official HMRC payment service
Check your tax calculation, outstanding balance and payment deadlines before making a payment.
Allow enough time for your payment to reach HMRC. Processing times differ depending on the payment method.
What happens if you cannot pay your Self Assessment bill?
Contact HMRC as soon as possible if you cannot pay the full amount by the deadline.
Depending on your circumstances, you may be able to arrange a Time to Pay agreement to spread your outstanding tax liability over an agreed period.
Interest can continue to apply to outstanding tax under a payment arrangement.
Do not ignore a tax bill simply because you cannot afford to pay it immediately. Contacting HMRC and discussing your circumstances can help you establish the available options.
12. Making Tax Digital for Income Tax: What changes for sole traders in 2026/27?
Making Tax Digital for Income Tax changes how eligible sole traders and landlords maintain accounting records and report their income to HMRC.
From 6 April 2026, qualifying sole traders and landlords became required to use compatible software for digital record-keeping, quarterly updates and their annual tax return.
The initial threshold is based on qualifying gross income exceeding £50,000 in the 2024/25 tax year, subject to the relevant eligibility and exemption rules.
Who must use Making Tax Digital for Income Tax?
The mandatory reporting requirements are being introduced in stages.
| Qualifying income | Assessment tax year | Mandatory start date |
|---|---|---|
| More than £50,000 | 2024/25 | 6 April 2026 |
| More than £30,000 | 2025/26 | 6 April 2027 |
| More than £20,000 | 2026/27 | 6 April 2028 |
Qualifying income generally refers to combined gross income from self-employment and property before expenses, calculated under the applicable rules.
It is not the same as taxable business profit.
Example: A sole trader with rental income
Suppose a self-employed consultant has:
| Income source | Annual gross income |
|---|---|
| Self-employment turnover | £38,000 |
| Property income | £15,000 |
| Combined qualifying income | £53,000 |
The consultant’s combined qualifying income exceeds £50,000.
If these figures were reported in the relevant 2024/25 tax return and the other eligibility requirements are met, the consultant would generally be required to use Making Tax Digital for Income Tax from 6 April 2026.
This is important because looking only at the consultant’s £38,000 business turnover would give an incomplete picture of their potential Making Tax Digital obligations.
What does Making Tax Digital require?
Eligible individuals must generally use compatible software to:
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Create, maintain and correct digital records of relevant business and property income and expenses.
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Submit quarterly summaries to HMRC.
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Complete the relevant year-end tax reporting process.
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Submit their annual tax return through compatible software.
Quarterly updates are not separate quarterly tax returns. They are summaries of income and expenses recorded during the year.
Making Tax Digital quarterly deadlines for 2026/27
For individuals using standard tax-year update periods, the relevant deadlines are:
| Reporting period | Submission deadline |
|---|---|
| 6 April – 5 July 2026 | 7 August 2026 |
| 6 April – 5 October 2026 | 7 November 2026 |
| 6 April 2026 – 5 January 2027 | 7 February 2027 |
| 6 April 2026 – 5 April 2027 | 7 May 2027 |
The standard updates are cumulative, meaning each update covers the period from the beginning of the tax year to the end of the relevant reporting period.
The first 2026/27 quarterly deadline has already passed. If you were required to use Making Tax Digital from April 2026 and have not yet submitted your first update, you should check your position promptly.
HMRC has confirmed that penalty points will not be applied for missed quarterly update deadlines during the 2026/27 tax year. However, digital records must still be maintained, and the required updates must be submitted before the annual tax return can be completed.
Does Making Tax Digital replace annual Self Assessment?
No. Making Tax Digital changes the reporting process, but it does not eliminate the requirement to complete an annual tax return or pay the tax due.
Individuals who are required to use Making Tax Digital must complete the applicable annual reporting process through compatible software.
The annual filing and payment deadline remains 31 January following the relevant tax year.
For the 2026/27 tax year, the annual tax return deadline is 31 January 2028.
Accfirm advice: Check your Making Tax Digital eligibility before choosing accounting software. If your business has multiple income sources, discuss the combined qualifying income rules with a qualified accountant.
13. Do sole traders need to register for VAT?
Sole traders must generally register for VAT if their taxable turnover exceeds £90,000 over a rolling 12-month period or they expect taxable turnover to exceed £90,000 in the next 30 days alone.
VAT registration is separate from Self Assessment registration.
For example, a sole trader with taxable turnover of £100,000 and allowable expenses of £65,000 may have a trading profit of £35,000.
The £35,000 profit is relevant to the sole trader’s personal tax calculation.
However, the £100,000 taxable turnover is relevant when assessing compulsory VAT registration.
The owner cannot avoid the VAT registration requirement simply because business expenses significantly reduce taxable profit.
Sole traders below the compulsory VAT registration threshold may choose to register voluntarily.
VAT-registered businesses must also comply with the relevant VAT accounting, record-keeping and reporting requirements.
14. How long must sole traders keep their Self Assessment records?
HMRC generally requires self-employed individuals to retain their business records for at least five years after the 31 January submission deadline for the relevant tax year.
For the 2026/27 tax year, this normally means retaining business records until at least the end of January 2033.
Special rules may require records to be kept for longer in particular circumstances, including very late returns.
What records should you retain?
Keep suitable evidence of your business transactions and tax calculations, including sales invoices, customer receipts, expense records, bank statements, relevant asset purchases and other documents supporting your tax return.
If you use accounting software, maintain access to the relevant records and ensure that you can retrieve the information if HMRC requests it.
It is also sensible to retain copies of submitted returns, tax calculations, payment confirmations and relevant correspondence with HMRC.
What happens if HMRC asks to check your records?
HMRC may request evidence supporting figures included in your tax return.
You should be able to explain how you calculated your business income, expenses and taxable profits.
Accurate records can help you respond to questions and identify genuine errors before they become more serious tax issues.
15. What are the penalties for late Self Assessment filing?
HMRC can impose penalties if you submit a required Self Assessment return after the applicable filing deadline or fail to pay your tax bill on time.
The penalty rules depend on the relevant tax year and whether you are within the standard Self Assessment system or the newer Making Tax Digital penalty regime.
Standard Self Assessment late filing penalties
For tax returns subject to the existing standard penalty regime, HMRC’s penalties include:
| How late is the tax return? | Potential penalty |
|---|---|
| Immediately after the filing deadline | Initial £100 penalty |
| More than 3 months late | £10 per day, up to £900 |
| More than 6 months late | Additional 5% of tax due or £300, whichever is greater |
| More than 12 months late | Further 5% of tax due or £300, whichever is greater |
The initial £100 late filing penalty can apply even if you do not have any tax to pay.
For returns covered by this regime, late payment can also result in interest and penalties linked to the amount of unpaid tax.
If you are required to use Making Tax Digital for Income Tax, check the separate penalty rules applicable from the tax year you enter that system.
Can you appeal a Self Assessment penalty?
Yes. You may be able to appeal an HMRC penalty if you have a valid reason and meet the applicable appeal requirements.
HMRC considers whether the circumstances amount to a reasonable excuse under the relevant rules.
If you receive a penalty notice that you believe is incorrect, check the reason for the penalty and the relevant appeal instructions.
Do not assume that having little or no tax to pay automatically removes a late filing penalty.
16. Can you amend a Self Assessment tax return after submitting it?
Yes. You can generally amend a Self Assessment return within 12 months of the relevant filing deadline.
For example, the normal amendment deadline for a 2026/27 Self Assessment return is 31 January 2029.
If you discover an error after the normal amendment period has ended, you may need to contact HMRC or make an appropriate claim using a different procedure.
Common reasons for amending a tax return
You may need to correct your return because:
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You omitted relevant business income.
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You included an expense that was not allowable.
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You forgot to claim qualifying business expenses.
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Your employment income or PAYE figures were incorrect.
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You made an error when calculating your trading profit.
If an amendment increases the tax due, HMRC may charge interest on the additional amount.
If the amendment reduces your liability, you may be entitled to a refund or an adjustment to your tax account.
For individuals using Making Tax Digital, amendments to returns submitted through that system should normally be made through compatible software.
17. Frequently asked questions about Sole Trader Self Assessment
Do sole traders have to complete Self Assessment every year?
Sole traders who are required to submit Self Assessment returns must generally continue filing for each relevant tax year until HMRC confirms that a return is no longer required. Stopping trading or earning less than £1,000 does not automatically cancel an existing filing requirement.
Can a sole trader complete Self Assessment without an accountant?
Yes. You can complete your own Self Assessment return using HMRC’s online service or appropriate tax software. However, professional support can be useful if you have multiple income sources, complex business expenses, capital allowances or Making Tax Digital obligations.
How much can a sole trader earn before paying Income Tax?
For 2026/27, the standard Personal Allowance is £12,570. If you qualify for the full allowance and have no other taxable income, you can normally earn up to £12,570 in taxable trading profit without paying Income Tax. National Insurance and other reporting obligations must be considered separately.
Do I need to complete Self Assessment if my sole trader business makes a loss?
You may still need to submit a tax return if HMRC has required you to file one. Reporting a genuine trading loss may also allow you to claim relief under the applicable rules. The availability and treatment of loss relief depend on your circumstances and the accounting method used.
Can I submit my Self Assessment tax return before January?
Yes. You can generally submit your annual Self Assessment tax return after the relevant tax year has ended and the filing service is available. For example, the 2025/26 tax year ended on 5 April 2026, and its standard online filing deadline is 31 January 2027.
Do I need to report my employment income as well as sole trader income?
Yes, if you are employed and self-employed, your Self Assessment return normally includes relevant employment income and tax deducted through PAYE, as well as your self-employment income. HMRC uses the combined information to calculate your overall personal tax position.
Is Self Assessment the same as VAT?
No. Self Assessment is the system used to report your personal taxable income and calculate relevant tax liabilities. VAT is a separate tax on supplies of goods and services. A sole trader can have Self Assessment obligations without being VAT registered.
Does Making Tax Digital mean I must pay Income Tax every three months?
No. Making Tax Digital introduces quarterly income and expense reporting for eligible individuals. Quarterly updates do not automatically create quarterly Income Tax payment obligations. The normal Self Assessment payment deadlines continue to apply.
What happens if I stop being a sole trader?
You should notify HMRC when you cease self-employment and complete any outstanding tax returns and payment obligations. If you no longer meet the requirements for Self Assessment, you can ask HMRC to withdraw future filing requirements where appropriate.
Is Self Assessment different for limited company directors?
A director’s personal Self Assessment return is separate from a company’s Corporation Tax return. A director may need to report salary, dividends, taxable benefits and other relevant personal income. If the director also runs a separate sole trader business, that business’s taxable income may need to be included in their personal return.
18. How Accfirm can help with your Sole Trader Self Assessment
Completing a Self Assessment return involves more than entering business income and expenses into an online form.
You must understand which expenses qualify for tax relief, how different income sources affect your tax position and whether payments on account or Making Tax Digital obligations apply.
For sole traders managing their own bookkeeping alongside day-to-day business activities, professional accounting support can help reduce administrative work and improve the accuracy of financial reporting.
Accfirm provides accounting and tax support for UK sole traders, freelancers and small business owners.
Our sole trader accountants can assist with understanding and managing areas such as:
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Self Assessment registration and preparation of annual tax returns.
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Business bookkeeping and financial record-keeping.
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Calculating trading profits and reviewing allowable expenses.
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VAT registration and ongoing accounting requirements.
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Making Tax Digital readiness and compatible accounting software.
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Tax payment planning and HMRC correspondence.
Whether you are preparing your first tax return or reviewing the accounting arrangements for an established business, Accfirm can help you understand your responsibilities and plan your next steps.
Need help with your Sole Trader Self Assessment?
Get professional guidance on Self Assessment, bookkeeping, allowable expenses and HMRC reporting requirements.
Final thoughts: Stay organised and meet your Self Assessment deadlines
Sole Trader Self Assessment becomes easier to manage when you maintain accurate business records, understand your tax obligations and prepare your return well before the filing deadline.
For the 2026/27 tax year, the standard online tax return and balancing payment deadline is 31 January 2028.
However, individuals completing their 2025/26 returns must meet the earlier deadline of 31 January 2027.
If you are within Making Tax Digital for Income Tax, ensure that your digital records and quarterly updates are up to date and that you follow the applicable annual tax return process.
The most important step is to plan for your tax bill throughout the year rather than waiting until January.
If you need assistance with your Self Assessment return or have questions about your individual tax position, speak with a qualified accountant at Accfirm.