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Tax year 2026/27
United Kingdom
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United Kingdom
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Tax year 2026/27
🇬🇧 United KingdomTax year 2026/27 · 6 Apr 2026–5 Apr 2027Sole traders · England, Wales, Scotland, NI

Self-employed Tax Calculator 2026/27

Estimate the Income Tax and Class 4 National Insurance on your 2026/27 sole-trader profits — on their own or on top of a PAYE job — and how much to set aside each month.

Self-employed tax

Sole trader · tax year 2026/27
Advanced: other income, pension, student loan
Used to work out which band your profit falls into.
Net amount paid — the provider adds 25% basic-rate relief.
Profit after tax
£32,868 per year · £2,739 a month

£40,000 profit − £5,486 Income Tax − £1,646 Class 4 NI

Trading profit£40,000
Income Tax£5,486
Class 4 NI£1,646
Set aside per month£594

Breakdown

ItemAmount
Turnover£50,000.00
Allowable expenses−£10,000.00
Trading profit£40,000.00
Income Tax−£5,486.00
Class 4 National Insurance−£1,645.80
Profit after tax£32,868.20

Where your profit goes

  • Kept (82%)£32,868
  • Income Tax (14%)£5,486
  • Class 4 NI (4%)£1,646
Effective rate17.8%

Income Tax + Class 4 NI as a share of profit.

Assumptions

  • England Income Tax rules for 2026/27; accounts drawn up to the tax year (basis period reform means profits are taxed for the tax year).
  • Class 2 NI is treated as paid because profits are at least £7,105.
  • Payments on account, losses brought forward and capital allowances are not modelled.

How this was calculated

trading profit = turnover − allowable expenses (or − £1,000 trading allowance)
Income Tax     = tax on (profit + other income) − tax on other income alone
Class 4 NI     = 6% × profit £12,570–£50,270 + 2% × profit above £50,270
profit after tax = profit − Income Tax − Class 4 NI − student loan

Your profit is taxed together with any salary, pension or rental income, so a side business on top of a job is often taxed at 20% or 40% from the first pound. This calculator shows the extra tax your profit causes, which is what you need to set aside.

Worked examples

Self-employed examples
ScenarioProfit after tax
£40,000 profit, no other income: tax £5,486, Class 4 £1,645.80£32,868
£7,000 side profit on a £35,000 salary: tax £1,400, Class 4 £0£5,600

Self Assessment tax is due by 31 January after the tax year. If your bill is over £1,000, HMRC usually also asks for two payments on account towards next year, each half of this year’s bill — budget for that in your first year.

Official sources

Rule review

Jurisdiction
United Kingdom
Tax year
2026/27 (6 Apr 2026–5 Apr 2027)
Rule version
uk-2026-27.1
Last reviewed
Review
Rates checked against the GOV.UK/HMRC pages listed; formulas covered by automated boundary tests.

Results are estimates for general information, not personalised tax, legal or financial advice. See our methodology and disclaimer.

Continue the decision with the next tool.

View all UK tools →

National Insurance

Employee, employer and self-employed NI estimates.

Income Tax

Personal Allowance, tax bands and effective rate.

Dividend Tax

Stack dividends with other income and apply the £500 allowance.

VAT

Add or remove 20%, 5% or zero-rated VAT.

Frequently asked questions

What is the trading allowance?
You can deduct a flat £1,000 instead of actual expenses. If your total trading income is £1,000 or less you do not need to report it. It is useful when your real expenses are low.
Do I still pay Class 2 NI?
No compulsory Class 2 is charged. If profits are £7,105 or more you are treated as having paid it for State Pension and benefit purposes. Below that you can pay voluntarily.
Why is my side income taxed at 20% from the first pound?
Your salary has already used your £12,570 Personal Allowance, so all of your profit falls in the basic-rate (or higher-rate) band. Class 4 NI is still charged only on profits above £12,570.
How much should I save for tax?
As a rough guide, set aside the monthly figure shown. For £40,000 of profit with no other income that is about £594 a month.
Are pension contributions tax-deductible for the self-employed?
Personal pension contributions get basic-rate relief added by the provider, and higher-rate taxpayers claim more through Self Assessment by extending the basic-rate band. The calculator applies that band extension.
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