UK self-employed tax calculator 2026
The calculator estimates your take-home profit as a UK self-employed person under Self Assessment for tax year 2026-27 (6 April 2026 – 5 April 2027). It deducts Income Tax at HMRC Self Assessment rates (20 % basic, 40 % higher, 45 % additional; Scottish rates differ), Class 4 National Insurance (6 % on profits between £12,570 and £50,270, then 2 % above), and voluntary Class 2 NI where applicable. Enter your net trading profit — the figure after allowable business expenses but before any tax.
| Trading profit | £40,000.00 |
| Income Tax (Self Assessment) | -£5,486.00 |
| National Insurance (Class 4) | -£1,645.80 |
| National Insurance (Class 2, voluntary) | -£0.00 |
| Net after tax | £32,868.20 |
Effective deduction rate 17.8 % · of which income tax 13.7 %
How this is calculated
- Start with your net trading profit — the income from self-employment after deducting allowable business expenses but before any tax. If your annual income from self-employment is £1,000 or less, you may claim the trading allowance instead of filing a Self Assessment return.
- Subtract any pension contributions that reduce Adjusted Net Income, then determine your Personal Allowance using the same taper as for employees: full £12,570 up to ANI of £100,000, reducing to zero at £125,140.
- Calculate Income Tax on taxable income (ANI minus Personal Allowance) using the same rUK or Scottish bands as for employees — self-employed income is taxed under Self Assessment, but the band boundaries and rates are identical.
- Calculate Class 4 National Insurance on trading profit: 6% on profits between the Lower Profits Limit (£12,570) and the Upper Profits Limit (£50,270), then 2% above £50,270. Note that Class 4 is assessed on trading profits, not on Adjusted Net Income.
- For Class 2 NI: if your trading profit is at or above the Small Profits Threshold (£7,105), Class 2 is treated as paid at zero cost and your National Insurance record is protected automatically. If your profit is below £7,105 and you wish to protect your State Pension record, you may opt to pay voluntary Class 2 at £3.65 per week (£189.80 per year).
- Your net after tax equals trading profit minus total Income Tax, minus Class 4 NI, minus any voluntary Class 2 paid. Payment is made through Self Assessment: payments on account by 31 January in the tax year and 31 July after, with a balancing payment by 31 January following the end of the tax year.
FAQ
How is self-employed National Insurance different from employee National Insurance?
Self-employed people pay Class 4 NI (6% on profits between £12,570 and £50,270, then 2% above) instead of the employee Class 1 NI (8%/2%). Crucially, you do not pay employer (Class 1 secondary) NI on your own profits — that saving is one of the NI advantages of self-employment. Class 2 NI, which protects your State Pension record, is treated as paid at no cost once profits exceed the Small Profits Threshold of £7,105.
What counts as trading profit for the purposes of this calculator?
Trading profit is your total self-employment income minus allowable business expenses — costs incurred wholly and exclusively for the purposes of the trade. This is the figure before Income Tax and National Insurance. Capital expenditure and personal costs are not deductible. If you have multiple trades, combine the profits (or offset losses) from all of them before entering the figure.
When do I need to make payments on account?
HMRC requires two advance payments on account if your Self Assessment tax liability for the previous year was £1,000 or more and more than 20% of your income was not taxed at source. Each payment on account is 50% of the prior year liability: the first is due 31 January during the tax year, the second by 31 July after the year ends. A balancing payment settling the difference between actual liability and payments on account is due the following 31 January.
Do pension contributions reduce my tax and National Insurance bill?
Pension contributions reduce your Adjusted Net Income, which reduces Income Tax. However, they do not reduce Class 4 NI — Class 4 is assessed on trading profits, not on Adjusted Net Income. Pension contributions can also recover a lost Personal Allowance if your profit is between £100,000 and £125,140, where the effective marginal rate on income tax reaches 60% (rUK) or 67.5% (Scotland) due to the Personal Allowance taper.
What happens if my profit is below the Personal Allowance?
If your trading profit is at or below £12,570, you owe no Income Tax and no Class 4 NI (both start at the same threshold). If your profit is also below the Small Profits Threshold (£7,105), Class 2 NI is not automatically credited, but you can still protect your State Pension record by paying voluntary Class 2 at £3.65 per week. You need 35 qualifying years for a full new State Pension, so gaps can be costly to fill later.
Official sources
Data last verified 2026-07-17 · tax year 2026 · 104 sourced values
Every rate, threshold and formula is read from a versioned dataset of official primary sources — no numbers are hardcoded. Values without a published 2026 primary source are flagged, never guessed.
12 sources
- HMRC / GOV.UK — Income Tax rates and Personal Allowances
- HMRC / GOV.UK — Income Tax Personal Allowance and the basic rate limit — thresholds from 6 April 2026 to 5 April 2028
- HMRC / GOV.UK — Scottish Income Tax
- HMRC / GOV.UK — Rates and thresholds for employers 2026 to 2027
- HMRC / GOV.UK — Tax on dividends
- HMRC / GOV.UK — Income Tax rates and allowances — current and past
- HMRC / GOV.UK — National Insurance rates and categories
- HMRC / GOV.UK — Rates and allowances: National Insurance contributions
- HMRC / GOV.UK — Special rules for student loans
- HMRC / GOV.UK — 2026-27 student and postgraduate loan deduction tables (SL3)
- HMRC / GOV.UK — Pension schemes: rates and allowances
- DWP / GOV.UK — Review of the automatic enrolment earnings trigger and qualifying earnings band for 2026/27
⚠️ Informational estimate, not tax advice. Payroll software may differ in edge cases. Verify with a professional.
United Kingdom tax guides
- How Income Tax Works in the UK (2026-27): Bands, Allowances and Rates →
- Employee National Insurance in the UK (2026-27): Rates, Thresholds and State Pension →
- Self-Employed Tax in the UK (2026-27): Income Tax, Class 4 NI and Self Assessment →
- How VAT Works in the UK (2026-27): Rates, Registration Threshold and Calculations →
- Debt Relief & Personal Insolvency in the United Kingdom (2026): How It Works →