Overview
This self-employed tax calculator estimates the Self Assessment bill for a UK sole trader in the 2026/27 tax year — income tax, Class 4 National Insurance, student loan repayments and payments on account — and tells you how much to set aside each month. Enter your turnover and allowable expenses (and any employment income or pension contributions), choose England, Wales & NI or Scotland, and you'll see your taxable profit, total tax and NI, your take-home, and your estimated January and July payments. It's built to answer the question every sole trader asks: "how much should I be saving for tax?"
How it's calculated
We work out your bill step by step:
- Profit = turnover − allowable expenses.
- Income tax on your profit (plus any employment income), after the Personal Allowance, using your region's bands.
- Class 4 National Insurance on profit: 6% between £12,570 and £50,270, then 2% above.
- Class 2 NI is treated as paid for 2026/27 — most sole traders no longer pay it.
- Student loan repayments, if any, at 9% (or 6% postgraduate) over the plan threshold.
- Payments on account — advance instalments toward next year's bill.
Set aside monthly = (income tax + Class 4 NI + student loan − PAYE already paid) ÷ 12
Personal pension contributions get relief by extending your basic-rate band, so higher-rate taxpayers pay less. Payments on account apply once your Self Assessment bill tops £1,000.
Worked example
A sole trader in England with £60,000 turnover and £10,000 of expenses (a £50,000 profit):
| Taxable profit | £50,000 | |
|---|---|---|
| Income tax | − £7,486 | |
| Class 4 National Insurance | − £2,246 | |
| Total tax & NI | £9,732 | |
| Set aside each month | ≈ £811 |
On a £50,000 profit you'd owe about £9,732 in tax and National Insurance — so setting aside roughly £811 a month keeps you covered. You'd take home around £40,268 for the year, before payments on account are factored into the timing.
Current rates & key facts
Self-employed tax & NI (2026/27)
| Item | Detail |
|---|---|
| Class 4 NI | 6% on profit £12,570–£50,270, then 2% above |
| Class 2 NI | Treated as paid — not required for most (voluntary below £6,845) |
| Payments on account | Apply once your Self Assessment bill exceeds £1,000 |
| Key dates | Balancing payment + 1st payment on account by 31 Jan; 2nd by 31 July |
A guide for sole traders. It excludes VAT, dividends, capital allowances and the High Income Child Benefit Charge, and is not a substitute for filing your Self Assessment return.
Last updated 1 July 2026 · Source: GOV.UK — Self-employed National Insurance rates