Working for yourself gives you control over how you earn, but it also means taking responsibility for your own tax.
Unlike an employee whose Income Tax and National Insurance are normally deducted automatically through PAYE, a sole trader usually needs to calculate their taxable business profit, report it to HMRC and budget for the resulting Self Assessment bill.
That is where a self-employed tax calculator becomes useful.
A calculator can give you an early estimate of how much Income Tax and Class 4 National Insurance you may owe for the 2026/27 tax year. It can also help you understand how allowable business expenses affect your tax bill and how much money you may want to put aside.
For 2026/27, the standard Personal Allowance remains £12,570. For taxpayers in England, Wales and Northern Ireland, the main Income Tax rates remain 20%, 40% and 45%. Self-employed Class 4 National Insurance is charged at 6% on relevant profits between £12,570 and £50,270 and 2% above £50,270.
This Accfirm guide explains how a UK self-employed tax calculator works, which figures you should enter, the 2026/27 tax rates and thresholds, and why the result may differ from your final HMRC Self Assessment calculation.
What Is a Self-Employed Tax Calculator?
A self-employed tax calculator estimates the Income Tax and National Insurance that may be due on profits from self-employment.
For a straightforward sole trader, the basic calculation usually starts with:
Business turnover − allowable business expenses = trading profit
The calculator can then apply the relevant Personal Allowance, Income Tax bands and Class 4 National Insurance rates.
For example:
| Calculation | Amount |
|---|---|
| Business turnover | £50,000 |
| Allowable expenses | £10,000 |
| Trading profit | £40,000 |
| Income Tax and NI | Calculated on applicable profit |
| Estimated amount left after Income Tax and Class 4 NI | Calculator result |
The important point is that a sole trader is generally taxed on profit rather than turnover.
HMRC allows self-employed individuals to deduct qualifying business expenses when calculating taxable profits.
How Does the Accfirm Self-Employed Tax Calculator Work?
A self-employed tax calculator should normally ask for figures such as your annual business income and allowable business expenses.
It can then estimate:
- Your trading profit.
- Your taxable income.
- Your Personal Allowance.
- Estimated Income Tax.
- Estimated Class 4 National Insurance.
- Combined Income Tax and National Insurance.
- Estimated income remaining after tax.
If you place the Accfirm calculator above this guide, users can enter their estimated annual figures and immediately see an approximate 2026/27 tax position.
The result should be treated as an estimate rather than a substitute for a complete Self Assessment tax calculation.
Self-Employed Tax Rates for 2026/27
Understanding the tax bands used by the calculator makes the results much easier to interpret.
Personal Allowance for 2026/27
The standard UK Personal Allowance for 2026/27 is:
£12,570
This means an individual can generally receive up to £12,570 of income before Income Tax becomes payable, assuming they are entitled to the full Personal Allowance.
However, the Personal Allowance starts to reduce where adjusted net income exceeds £100,000.
HMRC reduces the allowance by £1 for every £2 of adjusted net income above £100,000.
The Personal Allowance is therefore completely removed once adjusted net income reaches £125,140.
This taper can significantly increase the effective tax burden for higher earners.
Income Tax Rates for Self-Employed People in England, Wales and Northern Ireland
For 2026/27, the main rates are:
| Band | Taxable income after Personal Allowance | Rate |
|---|---|---|
| Basic rate | Up to £37,700 | 20% |
| Higher rate | £37,701 to £125,140 | 40% |
| Additional rate | Above £125,140 | 45% |
With the standard £12,570 Personal Allowance, the higher-rate threshold is effectively £50,270 of total income for someone entitled to the full allowance.
These rates apply to relevant non-savings, non-dividend income in England, Wales and Northern Ireland.
Scottish taxpayers have different bands, which we cover later.
Self-Employed National Insurance Rates for 2026/27
National Insurance is separate from Income Tax.
For most sole traders, the main contribution relevant to the tax calculation is Class 4 National Insurance.
Class 4 National Insurance
For 2026/27:
| Self-employed profit | Class 4 NI rate |
|---|---|
| Up to £12,570 | 0% |
| £12,571 to £50,270 | 6% |
| Above £50,270 | 2% |
HMRC confirms that Class 4 National Insurance is payable on relevant profits above £12,570.
This means Class 4 NI does not simply apply at 6% to all of your profit.
Only the part falling inside each applicable band is charged at that rate.
What Happened to Class 2 National Insurance?
The Class 2 rules changed significantly from April 2024.
For 2026/27, self-employed people with profits of £7,105 or more are generally treated as having paid Class 2 National Insurance for the purposes of protecting their National Insurance record. They do not normally have an actual Class 2 liability to pay.
If profits are below £7,105, voluntary Class 2 contributions may be available.
The voluntary Class 2 rate for 2026/27 is £3.65 per week.
A simple self-employed tax calculator will therefore usually focus on Income Tax and Class 4 NI rather than automatically adding Class 2 contributions.
How Is Self-Employed Tax Calculated?
The calculation can be broken into several steps.
Step 1: Calculate Your Business Turnover
Turnover is the gross amount your business earns before deducting expenses.
For example:
Client income: £65,000
Other business income: £5,000
Total turnover: £70,000
Turnover should not be confused with profit.
Step 2: Deduct Allowable Business Expenses
You can generally deduct qualifying costs incurred for your business.
Common sole trader expenses include:
- Office costs.
- Business phone and internet costs.
- Advertising and marketing.
- Business insurance.
- Business travel.
- Staff and subcontractor costs.
- Accountancy and professional fees.
- Software subscriptions.
- Business premises costs.
- Eligible equipment.
- Relevant training.
HMRC allows qualifying self-employed business expenses to be deducted when calculating taxable trading profit.
Suppose your turnover is £70,000 and you incur £15,000 of qualifying expenses.
Your trading profit would be:
£70,000 − £15,000 = £55,000
It is the £55,000 profit, rather than the £70,000 turnover, that generally forms the starting point for your Income Tax and Class 4 NI calculation.
Step 3: Apply Your Personal Allowance
Assuming you have no other income and qualify for the full standard allowance:
£55,000 profit − £12,570 Personal Allowance = £42,430 taxable income
The £12,570 allowance does not reduce National Insurance in exactly the same way. Class 4 NI uses its own profit thresholds, although the main lower threshold is also £12,570 for 2026/27.
Step 4: Calculate Income Tax
Using £55,000 of profit:
First £37,700 of taxable income:
£37,700 × 20% = £7,540
Remaining taxable income:
£42,430 − £37,700 = £4,730
Higher-rate Income Tax:
£4,730 × 40% = £1,892
Total estimated Income Tax:
£9,432
Step 5: Calculate Class 4 National Insurance
For £55,000 of trading profit:
Profit between £12,570 and £50,270:
£37,700 × 6% = £2,262
Profit above £50,270:
£4,730 × 2% = £94.60
Estimated Class 4 National Insurance:
£2,356.60
Step 6: Add Income Tax and National Insurance
Income Tax: £9,432
Class 4 NI: £2,356.60
Estimated combined liability: £11,788.60
This simplified calculation assumes:
- You live in England, Wales or Northern Ireland.
- You have no other taxable income.
- You receive the full Personal Allowance.
- You have no pension adjustments.
- You have no student loan repayments.
- You have no Capital Gains Tax liability.
- You have no relevant tax reliefs or losses.
- Payments on account are excluded.
Your actual Self Assessment bill may therefore be different.
Self-Employed Tax Calculator Examples for 2026/27
The following examples illustrate the approximate Income Tax and Class 4 NI payable at different profit levels.
They assume the taxpayer lives in England, Wales or Northern Ireland and has no other income or adjustments.
| Trading profit | Income Tax | Class 4 NI | Estimated total | After Income Tax and Class 4 NI |
|---|---|---|---|---|
| £15,000 | £486.00 | £145.80 | £631.80 | £14,368.20 |
| £30,000 | £3,486.00 | £1,045.80 | £4,531.80 | £25,468.20 |
| £45,000 | £6,486.00 | £1,945.80 | £8,431.80 | £36,568.20 |
| £60,000 | £11,432.00 | £2,456.60 | £13,888.60 | £46,111.40 |
| £100,000 | £27,432.00 | £3,256.60 | £30,688.60 | £69,311.40 |
| £120,000 | £39,432.00 | £3,656.60 | £43,088.60 | £76,911.40 |
| £150,000 | £53,703.00 | £4,256.60 | £57,959.60 | £92,040.40 |
These figures are illustrative and should not be treated as individual tax advice.
Example: Self-Employed Tax on £30,000 Profit
Suppose a freelance designer makes £38,000 in sales and has £8,000 of allowable expenses.
Trading profit:
£38,000 − £8,000 = £30,000
Income Tax
£30,000 − £12,570 = £17,430 taxable.
£17,430 × 20% = £3,486
Class 4 National Insurance
£30,000 − £12,570 = £17,430.
£17,430 × 6% = £1,045.80
Total
Income Tax: £3,486
Class 4 NI: £1,045.80
Estimated tax and NI: £4,531.80
Estimated amount remaining from the £30,000 profit:
£25,468.20
Example: Self-Employed Tax on £60,000 Profit
Now consider a consultant with £60,000 of taxable trading profit.
Income Tax
Personal Allowance:
£12,570
Taxable income:
£60,000 − £12,570 = £47,430
Basic-rate tax:
£37,700 × 20% = £7,540
Higher-rate tax:
£9,730 × 40% = £3,892
Total Income Tax = £11,432
National Insurance
£37,700 × 6% = £2,262
£9,730 × 2% = £194.60
Class 4 NI = £2,456.60
Total estimated liability
£11,432 + £2,456.60 =
£13,888.60
Estimated amount after Income Tax and Class 4 NI:
£46,111.40
Why Turnover and Profit Are Not the Same
One of the most common mistakes when using a self-employed tax calculator is entering turnover when the calculator is asking for profit.
Consider:
Turnover: £80,000
Allowable expenses: £20,000
Trading profit: £60,000
You do not normally calculate your Income Tax as though the entire £80,000 were profit.
The £20,000 of qualifying business costs reduces your trading profit to £60,000.
This is why accurate bookkeeping and expense records matter.
What Expenses Can Reduce Self-Employed Tax?
Claiming legitimate allowable expenses can reduce taxable business profit.
Typical categories include:
- Business stationery and office supplies.
- Business telephone costs.
- Software and cloud services.
- Advertising.
- Website costs.
- Business insurance.
- Accountancy fees relating to business work.
- Eligible mileage and travel costs.
- Staff wages and subcontractors.
- Professional subscriptions.
- Premises expenses.
- Qualifying equipment and tools.
Private expenditure is not deductible simply because it was paid from a business bank account.
Where an expense has both private and business use, only the identifiable qualifying business element may be deductible.
For a detailed explanation, internally link this section to Accfirm’s Allowable Expenses for Sole Traders guide.
Should You Use the £1,000 Trading Allowance Instead?
The UK trading allowance can provide up to £1,000 of relief against qualifying trading income.
Where eligible gross trading income exceeds £1,000, you may be able to choose between:
- Deducting your actual allowable expenses, or
- Using the £1,000 trading allowance instead.
You cannot normally use the trading allowance and deduct actual expenses against the same qualifying trading income.
HMRC confirms that individuals with gross trading receipts above £1,000 can, where eligible, elect to deduct the trading allowance instead of their actual business expenses.
Example
Turnover: £8,000
Actual expenses: £300
Using expenses:
£8,000 − £300 = £7,700
Using trading allowance:
£8,000 − £1,000 = £7,000
In this simplified example, using the trading allowance gives the lower profit figure.
However:
Turnover: £20,000
Expenses: £5,000
Actual expenses produce:
£15,000 profit
Using the trading allowance produces:
£19,000 profit
In that situation, actual expenses would usually produce a lower taxable trading profit.
Do Self-Employed People Pay Tax Below £12,570?
Not necessarily.
If self-employment is your only income and you qualify for the full Personal Allowance, Income Tax will generally not arise until your total taxable income exceeds £12,570.
However, your circumstances may differ if you also receive:
- Employment income.
- Pension income.
- Rental income.
- Foreign income.
- Investment income.
- Other taxable income.
Your Personal Allowance is shared across your taxable income rather than being a separate £12,570 allowance exclusively for self-employment.
For example, if your salary has already used your entire Personal Allowance, additional taxable self-employed profits may be subject to Income Tax immediately.
What If You Are Employed and Self-Employed?
Many people have a PAYE job and run a side business.
For example:
Employment income: £35,000
Self-employed taxable profit: £12,000
You cannot apply a separate £12,570 Personal Allowance to both income sources.
Your employment income and self-employed taxable income generally contribute to your overall Income Tax position.
HMRC notes that someone who is both employed and self-employed may pay Class 1 National Insurance through employment and Class 4 NI on qualifying self-employed profits.
A simple calculator that only asks for self-employed profit may therefore underestimate your tax if you also have other income.
Does Scotland Have Different Self-Employed Income Tax Rates?
Yes.
Scottish taxpayers have different Income Tax bands for earnings and trading profits.
For 2026/27, the Scottish rates are:
| Total taxable income band with standard Personal Allowance | Rate |
|---|---|
| £12,571–£16,537 | 19% |
| £16,538–£29,526 | 20% |
| £29,527–£43,662 | 21% |
| £43,663–£75,000 | 42% |
| £75,001–£125,140 | 45% |
| Above £125,140 | 48% |
Scottish Income Tax applies to most non-savings, non-dividend income, including relevant self-employment profits.
Class 4 National Insurance remains based on the UK-wide National Insurance thresholds.
Therefore, a calculator designed only for England, Wales and Northern Ireland should clearly state that its Income Tax estimate is not suitable for Scottish taxpayers unless Scottish rates have been programmed into it.
What Are Payments on Account?
This is one of the most important areas a basic self-employed tax calculator may not fully reflect.
Payments on account are advance payments towards your next Self Assessment tax bill.
HMRC normally requires them unless:
- Your previous Self Assessment tax liability was less than £1,000, or
- More than 80% of the tax was collected outside Self Assessment.
Each payment is normally half of the previous year’s relevant Self Assessment liability.
Payments are generally due on:
31 January
and
31 July
Example
Suppose your first Self Assessment bill is £4,000.
Your first payment on account could be:
£4,000 ÷ 2 = £2,000
You may therefore need to pay:
Tax bill: £4,000
First payment on account: £2,000
Total due in January: £6,000
A further:
£2,000
may then be payable by 31 July.
This is why new sole traders are sometimes surprised by their first large January payment.
Your tax liability might be £4,000, but the immediate cash requirement could be higher because the first payment on account is also due.
Does a Tax Calculator Include Payments on Account?
Not always.
A calculator may show your underlying annual Income Tax and National Insurance liability without showing the additional cash payment required towards the following tax year.
This distinction matters.
If the calculator estimates:
Annual tax and NI: £8,000
your first January payment could potentially include:
- The balancing payment for the completed tax year.
- The first payment on account for the following year.
Always check whether the calculator result includes payments on account.
Accfirm has a separate guide explaining Payments on Account for Sole Traders, which is an ideal internal link from this section.
How Much Should a Self-Employed Person Put Aside for Tax?
There is no single percentage that works for every sole trader.
Your tax burden depends on:
- Your annual profit.
- Other income.
- Personal Allowance entitlement.
- Income Tax band.
- Scottish tax status.
- Class 4 National Insurance.
- Student loan repayments.
- Pension contributions.
- Payments on account.
- Allowable expenses.
- Tax reliefs.
Someone making £25,000 may have a very different effective rate from someone earning £100,000.
A practical approach is to run your updated profit through a self-employed tax calculator regularly and transfer an appropriate amount into a separate tax savings account.
Do not wait until January to work out whether you have enough cash available.
Self Assessment Deadlines for the 2026/27 Tax Year
The 2026/27 tax year runs from:
6 April 2026 to 5 April 2027
For a new taxpayer who needs to notify HMRC, the normal registration deadline for the 2026/27 liability is:
5 October 2027
The normal paper return deadline is:
31 October 2027
The standard online Self Assessment filing deadline is:
31 January 2028
The balancing payment is generally also due:
31 January 2028
The second payment on account, where applicable, would normally be due:
31 July 2028
HMRC confirms the standard Self Assessment pattern of 5 October notification, 31 October paper filing and 31 January online filing/payment, subject to particular exceptions.
When Do You Need to Register as Self-Employed?
You will normally need to submit a Self Assessment return if you were self-employed as a sole trader and had gross trading income of more than £1,000 before deducting expenses.
The £1,000 test relates to gross trading income, not taxable profit.
For example:
Turnover: £5,000
Expenses: £4,500
Profit: £500
Although your eventual profit is only £500, your gross trading income is £5,000.
You therefore cannot assume that being below the Personal Allowance removes the requirement to consider Self Assessment registration.
Making Tax Digital for Self-Employed People in 2026/27
Making Tax Digital for Income Tax is particularly important for sole traders using tax calculators and accounting software.
The first compulsory phase began on 6 April 2026.
You generally need to use MTD for Income Tax from 6 April 2026 if qualifying income shown on your 2024/25 tax return was more than £50,000, subject to the applicable conditions and exemptions.
HMRC’s rollout is:
| Relevant tax return | Qualifying income | MTD start |
|---|---|---|
| 2024/25 | Over £50,000 | 6 April 2026 |
| 2025/26 | Over £30,000 | 6 April 2027 |
| 2026/27 | Over £20,000 | 6 April 2028 |
Qualifying income is broadly total gross income from self-employment and property before expenses.
MTD users need compatible software to maintain relevant digital records and send quarterly updates to HMRC.
This makes ongoing bookkeeping increasingly important.
Rather than calculating your tax only once each January, maintaining accurate digital figures throughout the year gives you a much better view of your expected tax position.
Does a Self-Employed Tax Calculator Include VAT?
Normally, no.
VAT is separate from Income Tax and National Insurance.
For 2026/27, the UK VAT registration threshold remains £90,000 of taxable turnover.
This is another important distinction:
Income Tax calculations usually focus on profit.
VAT registration is generally based on taxable turnover.
For example:
Annual taxable turnover: £95,000
Expenses: £40,000
Profit: £55,000
Your tax calculator may calculate Income Tax and NI using the £55,000 profit.
However, the £95,000 taxable turnover may mean you need to consider VAT registration separately.
Do not use the profit shown by a self-employed tax calculator to assess the VAT registration threshold.
Can a Limited Company Director Use a Self-Employed Tax Calculator?
Usually not for company income.
A limited company director is not automatically self-employed simply because they own and work for their company.
HMRC treats a limited company as a separate entity.
Company profits may be subject to Corporation Tax, while the director may receive income through salary, dividends or other payments.
That requires a different calculation.
A sole trader tax calculator should therefore not be used to estimate the complete tax position of someone operating exclusively through a limited company.
However, a company director who separately earns income from genuine self-employment may need to calculate the self-employed activity alongside their other income.
What Is Not Usually Included in a Basic Self-Employed Tax Calculator?
Online calculators are useful planning tools, but personal tax can become complex.
A basic calculator may not correctly account for:
- Scottish Income Tax.
- Employment income.
- Rental income.
- Dividends.
- Savings income.
- Pension contributions.
- Gift Aid.
- Marriage Allowance.
- Blind Person’s Allowance.
- Trading losses.
- Losses brought forward.
- Student loan repayments.
- Postgraduate loan repayments.
- High Income Child Benefit Charge.
- Capital Gains Tax.
- Foreign income.
- CIS deductions already suffered.
- Pension annual allowance issues.
- Payments on account.
- Tax deducted at source.
- Basis period adjustments.
- Partnership profits.
- Multiple self-employed businesses.
If any of these apply, treat the calculator as a starting estimate rather than your final tax computation.
Why Your HMRC Tax Bill May Be Higher Than the Calculator Result
There are several reasons.
1. You have other income
Your Personal Allowance and tax bands apply across your overall taxable income.
2. Payments on account are due
The January cash payment may include both your balancing payment and an advance payment towards the next year.
3. Student loan repayments apply
Self Assessment can also calculate repayments where applicable.
4. Your Personal Allowance is reduced
Adjusted net income above £100,000 can reduce your Personal Allowance.
5. Some claimed expenses are not allowable
Your bookkeeping profit and taxable profit may differ.
6. You live in Scotland
Different Income Tax rates apply.
7. You have Capital Gains Tax or other liabilities
These are not necessarily included in a simple sole trader calculator.
Why Your Tax Bill Could Be Lower Than the Calculator Estimate
The opposite can also happen.
The calculator may not recognise:
- Pension tax relief.
- Gift Aid adjustments.
- Trading losses.
- Capital allowances.
- Certain tax reliefs.
- CIS tax already deducted.
- Payments already made on account.
- Tax deducted through PAYE.
That is why the final Self Assessment calculation should be prepared from your complete financial information.
Can Allowable Expenses Really Reduce Self-Employed Tax?
Yes.
Because Income Tax and Class 4 NI are calculated using taxable trading profits, legitimate business deductions can reduce the amount exposed to tax.
For example:
Turnover: £50,000
Expenses: £5,000
Profit: £45,000
Now assume the sole trader identifies another £2,000 of legitimate allowable expenses.
Revised profit:
£43,000
The £2,000 deduction reduces the amount on which Income Tax and potentially Class 4 NI are calculated.
However, spending £2,000 does not mean you receive £2,000 back from HMRC.
A business expense reduces taxable profit; it is not normally a pound-for-pound tax refund.
Common Self-Employed Tax Calculator Mistakes
Entering turnover instead of profit
Check exactly what the calculator is asking for.
Forgetting business expenses
Missing legitimate deductions can overstate taxable profit.
Claiming personal expenditure
Personal costs should not be included simply to reduce the calculator result.
Ignoring other income
Employment, property and other taxable income can push self-employed profit into a higher tax band.
Forgetting payments on account
The annual tax figure and the January payment requirement are not always the same.
Assuming Class 2 is still automatically charged
For 2026/27, qualifying self-employed individuals are generally treated as having paid Class 2 rather than being required to pay it.
Using England tax bands when you live in Scotland
Scottish Income Tax bands are different.
Using the calculator for a limited company
Sole trader and limited company tax calculations are fundamentally different.
How to Use a Self-Employed Tax Calculator More Accurately
Before entering figures, prepare:
- Your estimated annual business turnover.
- Your allowable business expenses.
- Any other employment income.
- Rental or property income.
- Pension contributions where relevant.
- Tax already deducted.
- CIS deductions where applicable.
- Payments on account already made.
Then compare the calculator result with your bookkeeping records.
Update the calculation during the year as your profit changes.
This is much more useful than making one estimate at the beginning of the year and never reviewing it.
Do Sole Traders Need an Accountant to Calculate Tax?
No.
You are not legally required to appoint an accountant simply because you are self-employed.
However, professional assistance can become valuable when you have:
- Higher business profits.
- Multiple income sources.
- VAT registration.
- Employees.
- CIS income or subcontractors.
- Rental income.
- Trading losses.
- Significant capital expenditure.
- Making Tax Digital obligations.
- Payments on account.
- Complex allowable expenses.
- Plans to incorporate your business.
A calculator can tell you approximately what the numbers mean.
An accountant can review whether the numbers going into the calculation are correct in the first place.
How Accfirm Can Help Self-Employed People
A self-employed tax calculator is useful for estimating your liability, but accurate tax planning begins with accurate business records.
Accfirm supports UK freelancers, contractors, sole traders and small business owners with bookkeeping, tax calculations, Self Assessment and ongoing compliance.
Our sole trader accountants can help you with:
- Calculating taxable trading profit.
- Reviewing allowable business expenses.
- Preparing Self Assessment tax returns.
- Calculating Income Tax and National Insurance.
- Understanding payments on account.
- Maintaining accurate bookkeeping records.
- Reviewing VAT registration requirements.
- Preparing for Making Tax Digital.
- Assessing whether remaining a sole trader is suitable as your business grows.
Professional support can be particularly useful where your actual circumstances are more complicated than the assumptions built into an online calculator.
Frequently Asked Questions
How much tax will I pay if I am self-employed?
The amount depends on your taxable profit, other income, Personal Allowance, Income Tax band and National Insurance position.
For 2026/27, a straightforward sole trader in England, Wales or Northern Ireland generally receives a £12,570 Personal Allowance, with Income Tax charged at 20%, 40% and 45% across the relevant bands. Class 4 National Insurance is generally 6% between £12,570 and £50,270 of relevant profit and 2% above £50,270.
How much can I earn self-employed before paying tax in 2026/27?
If self-employment is your only taxable income and you qualify for the full Personal Allowance, you would normally begin paying Income Tax once taxable income exceeds £12,570.
Different rules can apply where you have other income.
Do I pay National Insurance if I am self-employed?
Class 4 National Insurance is generally payable where relevant self-employed profits exceed £12,570.
For 2026/27, the rate is 6% up to £50,270 and 2% above that amount.
Do self-employed people still pay Class 2 National Insurance?
Most self-employed people no longer have a compulsory Class 2 payment liability.
If profits are at least £7,105 for 2026/27, Class 2 is generally treated as paid.
People below that level may choose to make voluntary Class 2 contributions where appropriate.
Is self-employed tax based on turnover or profit?
Income Tax is generally calculated using taxable trading profit rather than gross turnover.
Trading profit normally starts with business income minus allowable expenses and any relevant tax adjustments.
What is the difference between turnover and profit?
Turnover is the amount earned before expenses.
Profit is broadly the amount remaining after allowable business costs and relevant adjustments.
For example:
£50,000 turnover − £12,000 expenses = £38,000 business profit.
Does the calculator include expenses?
That depends on how the calculator is designed.
If it asks for turnover and expenses separately, it can calculate profit automatically.
If it asks for profit, you should deduct qualifying business expenses before entering the figure.
Do I need Self Assessment if I earn less than £12,570?
Possibly.
The Personal Allowance determines when Income Tax may become payable, but Self Assessment registration is a separate issue.
A sole trader with gross trading income above £1,000 normally needs to consider Self Assessment even if their final profit is below the Personal Allowance.
Does the calculator include payments on account?
Many calculators do not.
Payments on account can increase the amount actually due to HMRC in January and July even though they are advance payments towards the next tax year’s liability.
Can freelancers use a self-employed tax calculator?
Yes.
Freelance designers, developers, consultants, photographers, writers, marketers and many other independent professionals operating as sole traders can use the same basic principles.
Can an Uber driver use the calculator?
Yes, if they are operating as a self-employed sole trader and the calculator assumptions match their circumstances.
They should calculate qualifying income and allowable business expenses correctly before relying on the estimate.
Can a construction subcontractor use the calculator?
Yes, but CIS deductions require additional consideration.
Tax deducted under the Construction Industry Scheme may reduce the amount still payable through Self Assessment.
A calculator that ignores CIS deductions may therefore overstate the final payment due.
Can I use the calculator if I am VAT registered?
Yes, but VAT should be treated separately.
VAT registration and VAT payments are not the same as personal Income Tax and National Insurance.
Is the calculator accurate for Scottish taxpayers?
Only if it includes the Scottish Income Tax bands.
A calculator using only the 20%, 40% and 45% main UK rates will not accurately calculate Scottish non-savings, non-dividend Income Tax for 2026/27.
Final Thoughts: Estimate Your Self-Employed Tax Before the Deadline
A self-employed tax calculator gives you something extremely valuable: visibility.
Instead of reaching January without knowing how much tax you may owe, you can estimate your liability throughout the year, adjust for changing profits and put money aside before the deadline.
For 2026/27, remember the main figures:
- Personal Allowance: £12,570
- Basic Income Tax rate: 20%
- Higher rate: 40%
- Additional rate: 45%
- Class 4 NI: 6% between £12,570 and £50,270
- Class 4 NI: 2% above £50,270
- Class 2 Small Profits Threshold: £7,105
- VAT registration threshold: £90,000
- Online 2026/27 Self Assessment deadline: 31 January 2028
Most importantly, remember that a calculator is an estimate.
Your actual tax position may change because of other income, tax reliefs, pension contributions, losses, student loans, Scottish Income Tax, payments on account or other circumstances.
If you want your figures checked, speak with Accfirm or consult qualified sole trader accountants before submitting your Self Assessment return.