TaxReadySheets

Self-employed tax calculator for 2026/27: income tax, NI and take-home pay

Type in what your business brought in and what it cost to run. You will see the income tax and National Insurance on your profit, what you actually keep, and a monthly figure to move into a tax pot so January holds no surprises.

Checked for 2026/27 — uses the rates for 6 April 2026 to 5 April 2027, last reviewed 27 October 2026.

Your figures

Everything you invoiced or took in the tax year, before any costs.

Supplies, phone, insurance, software, business travel and similar.

Expenses or the £1,000 trading allowance?

Salary or pension taxed through PAYE. Used to work out your tax band; its tax is assumed already paid.

Tick if you live in Scotland. Class 4 NI is the same across the UK.

Your estimate

Put aside each month

£0

Taxable profit
£0.00
Income tax on your profit
£0.00
Class 4 National Insurance
£0.00
Total tax bill
£0.00
Take-home after tax
£0.00
Effective rate on profit
£0.00

Payments on account:

Results update as you type. No sign-up, and nothing you enter leaves your device.

Worked example

Sam is a sole trader in Manchester with £32,000 of sales and £2,000 of running costs in 2026/27, and no other job.

Turnover£32,000.00
Less expenses (beats the £1,000 allowance)−£2,000.00
Taxable profit£30,000.00
Personal allowance£12,570.00
Income tax: £17,430 × 20%£3,486.00
Class 4 NI: £17,430 × 6%£1,045.80
Total to pay£4,531.80
Take-home£25,468.20
Monthly set-aside (÷ 12)£377.65

Because Sam's bill is over £1,000 and none of it was taken at source, HMRC will also ask for payments on account of £2,265.90 each, towards the 2027/28 year. In the first January Sam would pay the £4,531.80 bill plus the first £2,265.90 instalment — £6,797.70 in one go. Planning for that is the main reason to save monthly from day one.

How it works, in plain English

Self-employed tax is worked out on profit, not on sales. Profit is your turnover minus allowable expenses. If your costs are small, you can instead knock a flat £1,000 trading allowance off your turnover; the calculator tries both and uses the one that leaves the smaller profit unless you tell it otherwise.

Income tax

Everyone gets a £12,570 personal allowance before any income tax is due. In England, Wales and Northern Ireland the next £37,700 is taxed at 20%, income up to £125,140 at 40%, and anything above that at 45%. Once your total income passes £100,000 the allowance shrinks by £1 for every £2 over, disappearing completely at £125,140. Scotland has six bands, from 19% to 48% — tick the Scotland box to use them.

If you also have a job, your salary uses up the allowance and lower bands first, so your business profit is taxed at your next rate. The calculator shows only the extra tax caused by your self-employment, because PAYE should already have taken the tax on your wages.

National Insurance

Class 4 is charged at 6% on profits between £12,570 and £50,270, and 2% on anything above. Class 2 no longer costs anything: with profits of £7,105 or more you are treated as having paid it and still build up State Pension years. Below that you can choose to pay £3.65 a week voluntarily to protect your record.

Why a monthly set-aside?

Nothing is taken from self-employed income as you earn it. The whole year's bill is due on 31 January after the tax year ends, and if it is over £1,000 HMRC usually adds advance payments on account for the next year — half on 31 January and half on 31 July. Moving the monthly figure into a separate savings account as you go is the simplest way to be ready.

Frequently asked questions

How much should I save for tax when self-employed?

Use the monthly set-aside figure above. As a rough rule, basic-rate sole traders often need about 15–25% of profit once income tax and Class 4 NI are added together, but the exact share depends on your profit and any other income. If you are in your first year, also allow for the first payment on account.

Do I pay tax on my turnover or my profit?

On your profit. Income tax and Class 4 National Insurance are both based on turnover minus allowable expenses (or minus the £1,000 trading allowance if that is bigger). Turnover only matters for things like the VAT registration threshold and Making Tax Digital.

Can I claim expenses and the trading allowance together?

No — for the same business it is one or the other. If your actual costs are under £1,000 the allowance usually wins; above £1,000, claiming real expenses gives a lower profit. This calculator compares both for you.

I have a full-time job as well. How is my side income taxed?

Your salary is taxed first through PAYE and uses up your personal allowance. Your self-employed profit then sits on top, so it is often taxed at 20% or 40% from the first pound. You still only pay Class 4 NI if the profit itself is over £12,570.

Do I need to pay Class 2 National Insurance?

No. Since April 2024 nobody has to pay Class 2. If your profit is £7,105 or more you get the State Pension credit automatically. Below that you can pay £3.65 a week voluntarily if you want to keep your National Insurance record complete.

When do I pay the tax for 2026/27?

The balance is due by 31 January 2028, the same day the online return is due. If you have payments on account, they fall on 31 January 2027 and 31 July 2027 for the 2026/27 year. See our Self Assessment deadlines guide for the full list.

Estimates only, not tax advice. These figures are a guide based on the information you enter and the 2026/27 rules. Your own position can differ — check GOV.UK or an accountant before relying on them.