Self-Employed Tax Calculator
Estimate UK sole trader tax on self-employed profit, including Income Tax, Class 4 National Insurance, Class 2 NI credit status, the trading allowance and likely payments on account. It is built for freelancers, contractors, sole traders and side-hustle sellers who want a clear Self Assessment estimate before the bill lands.
Estimate your sole trader tax bill
Enter annual figures for the tax year. Use gross figures before tax for other income.
Total sales or fees before expenses.
Use business-only costs, not personal spending.
Salary, pension or other taxable income before tax.
PAYE tax or other tax collected outside Self Assessment.
Taxable profit
£0
Income Tax
£0
Class 4 NI
£0
Estimated bill
£0
| Net profit | £0 |
| Income Tax | £0 |
| Class 4 National Insurance | £0 |
Personal Allowance
£12,570
Tapers by GBP 1 for every GBP 2 of adjusted net income above GBP 100,000.
Class 4 NI
6% / 2%
6% from GBP 12,570 to GBP 50,270, then 2% above GBP 50,270.
Trading allowance
£1,000
Can replace actual expenses, but cannot create a loss.
What this self-employed tax calculator is for
This calculator is for UK sole traders and freelancers who want to estimate the tax due through Self Assessment. It focuses on the core calculation: business turnover, allowable expenses, taxable profit, Income Tax, Class 4 National Insurance and likely payments on account.
The useful distinction is profit versus cash received. If you invoice GBP 50,000 and spend GBP 8,500 on allowable business costs, your starting profit is GBP 41,500. Income Tax and Class 4 National Insurance are worked from that profit, then other taxable income is used to decide which tax bands your self-employed profit falls into.
It is not a full Self Assessment return. Student loans, pension relief, Gift Aid, CIS deductions, VAT, capital allowances and losses can change the final figure. The calculator is designed to be a reliable planning estimate, not a substitute for HMRC software or an accountant.
| Input | Why it matters |
|---|---|
| Turnover | The total income from the trade. |
| Expenses | Deducted if you do not use the trading allowance. |
| Other income | Uses tax bands before your self-employed profit. |
| Tax deducted | Can affect payments-on-account warnings. |
How this calculator works
Inputs used
- Tax year, Income Tax region, self-employed turnover, allowable expenses, trading allowance choice, other taxable income and tax already deducted at source.
- Official Personal Allowance, Income Tax bands, Scottish Income Tax bands, Class 4 NI rates and Class 2 Small Profits Thresholds for the selected tax year.
Calculation method
- Calculate business profit from turnover minus actual expenses, or turnover minus the trading allowance if selected.
- Apply the Personal Allowance taper based on total income, including other taxable income.
- Calculate Income Tax on total income, then subtract the tax attributable to other income to estimate the tax attributable to self-employed profit.
- Calculate Class 4 National Insurance on self-employed profit only.
- Show Class 2 NI credit status using the Small Profits Threshold for the selected tax year.
- Estimate whether payments on account are likely by applying the GBP 1,000 rule and the 80% tax-collected-at-source exception.
Assumptions
- Other taxable income is treated as using tax bands before self-employed profit. This is a practical estimate for side-hustle and mixed-income planning.
- The calculator assumes the selected region applies for the full tax year.
- Trading allowance is capped at turnover and cannot create or increase a trading loss.
- Payments on account are estimated from this year's calculated Self Assessment bill. HMRC bases actual payments on your submitted return and account history.
What this does not cover
- Student loan repayments. Use the Student Loan Repayment Calculator for a separate estimate.
- VAT registration, VAT returns, Flat Rate Scheme calculations or import VAT. Use the VAT Calculator or VAT Flat Rate Scheme Calculator for those checks.
- CIS deductions and refunds. Use the CIS Tax Rebate Calculator if construction deductions are involved.
- Capital allowances, basis-period transitional rules, partnerships, foreign income, losses relief claims, pension tax relief, Gift Aid and High Income Child Benefit Charge.
Actual expenses or trading allowance?
If you keep receipts and your allowable business expenses are more than GBP 1,000, actual expenses will usually give the lower taxable profit. Typical costs include business software, insurance, accountancy, advertising, stock, business travel and the business proportion of phone or home-working costs.
If your costs are small, the trading allowance can be simpler. It lets you deduct up to GBP 1,000 instead of actual expenses, but it is not a magic extra allowance on top of real costs. You choose one route for that trade. If turnover is below GBP 1,000, the allowance is capped at turnover.
A quick example: turnover of GBP 6,000 with GBP 300 of expenses gives GBP 5,700 profit using actual expenses, but GBP 5,000 if you use the trading allowance. Turnover of GBP 6,000 with GBP 2,400 of genuine expenses is usually better with actual expenses.
The first-year bill shock
New sole traders often save for one tax bill and then discover payments on account. If your Self Assessment bill is GBP 3,000 and payments on account apply, you may need to pay GBP 3,000 for the year just ended plus a first payment on account of GBP 1,500 by 31 January, then another GBP 1,500 by 31 July.
The calculator separates the current bill from payment-on-account estimates so you can plan cash flow. It also lets you enter tax already deducted at source, because GOV.UK says payments on account are not normally required if last year you paid more than 80% of the tax owed outside Self Assessment.
If you expect profits to fall, you can ask HMRC to reduce payments on account, but do it carefully. If the reduction is too low, HMRC can charge interest on the shortfall.
Class 2 and Class 4 National Insurance
Class 4
Paid on self-employed profits above GBP 12,570. The main rate is 6% up to GBP 50,270, then 2% above that.
Class 2 credit
Above the Small Profits Threshold, Class 2 is usually treated as paid, helping protect your NI record.
Voluntary Class 2
Below the threshold, you may be able to pay voluntary Class 2 to avoid gaps in your National Insurance record.
Making Tax Digital warning
Making Tax Digital for Income Tax is now a live planning issue for sole traders and landlords. GOV.UK says you need to use MTD if you are registered for Self Assessment, have self-employment or property income, and your qualifying income is above the relevant threshold.
The current staged thresholds are: over GBP 50,000 from 6 April 2026 based on 2024/25 qualifying income, over GBP 30,000 from 6 April 2027 based on 2025/26 qualifying income, and over GBP 20,000 from 6 April 2028 based on 2026/27 qualifying income. This is about record keeping and reporting, not a new tax rate, but it can change how you keep books and submit updates.
Self-employed tax FAQs
Do I pay tax on turnover?
Do self-employed people still pay Class 2 National Insurance?
Can I use this if I also have a job?
What if I made a loss?
When do I need to register for Self Assessment?
Official sources
Last verified: May 12 2026. Calculations are estimates based on the published rules and assumptions shown on this page.
- GOV.UK Income Tax rates and Personal Allowance - Personal Allowance, taper over GBP 100,000, and UK Income Tax bands
- GOV.UK National Insurance rates and allowances - Class 2 Small Profits Threshold and Class 4 National Insurance rates
- GOV.UK trading allowance - GBP 1,000 trading allowance and when it can replace actual expenses
- GOV.UK payments on account - Self Assessment advance payment rules, GBP 1,000 and 80% exceptions
- GOV.UK self-employed expenses - official guidance on allowable business expenses
- Scottish Income Tax rates - current Scottish starter, basic, intermediate, higher, advanced and top rates
- GOV.UK Making Tax Digital for Income Tax - MTD qualifying income thresholds from 2026, 2027 and 2028
- GOV.UK Self Assessment deadlines - 5 October registration, 31 October paper return and 31 January online return/payment deadlines