Self-employed · Class 2 & Class 4

Self-employed National Insurance calculator

Work out the National Insurance you'll pay as a sole trader for the 2026/27 tax year from your profit — Class 4 on your earnings and where you stand on Class 2. It runs in your browser; nothing is sent anywhere.

Your self-employment

National Insurance is worked out on your profit — turnover minus your allowable business expenses — not your total turnover.

Self-employment turnover total takings for 6 April 2026 to 5 April 2027, before expenses

Allowable business expenses stock, mileage, tools, phone, the trading allowance — whatever you deduct

Self-employed National Insurance in 2026/27

Sole traders pay two kinds of National Insurance, both worked out on your profit for the tax year and both paid through Self Assessment alongside your income tax:

Class 4 — profits between £12,570 and £50,2706%
Class 4 — profits above £50,2702%
Class 2 — profits at or above £7,105 (Small Profits Threshold)£0, treated as paid
Class 2 — profits below £7,105 (voluntary, optional)£3.65 / week

What happened to Class 2?

Class 2 used to be a flat weekly charge. Since April 2024 you no longer pay it: if your profits are at or above the £7,105 Small Profits Threshold, Class 2 is treated as paid, so your National Insurance record still builds towards the State Pension and benefits without you paying anything. Only Class 4 actually costs you money. If your profits are below £7,105 you owe nothing, but you can choose to pay voluntary Class 2 at £3.65 a week to keep that qualifying year on your record.

How Class 4 is worked out

Class 4 is charged in two bands, the same shape as income tax. On the slice of profit between £12,570 and £50,270 you pay 6%; on anything above £50,270 you pay 2%. So a sole trader with £40,000 profit pays 6% of (£40,000 − £12,570) = £1,645.80. Nothing is due on the first £12,570 of profit, and nothing is due at all if your profit is £12,570 or less.

Class 4 doesn't count towards your State Pension — it's Class 2 (or the credit you get in its place) that protects your record. Class 4 is simply an extra charge on self-employed profit.

Common questions

How much National Insurance do I pay if I'm self-employed?

For 2026/27 you pay Class 4 at 6% on profits between £12,570 and £50,270, then 2% on profits above £50,270. Class 2 is £0 — it's treated as paid once your profits reach the £7,105 Small Profits Threshold. So a sole trader with £30,000 profit pays 6% of (£30,000 − £12,570) = £1,045.80 in National Insurance for the year.

Do I still have to pay Class 2 National Insurance?

Not if your profits are £7,105 or more — Class 2 is treated as having been paid, so your National Insurance record is protected and you pay nothing. If your profits are below £7,105 you don't have to pay anything either, but you can choose to pay voluntary Class 2 at £3.65 a week to keep the year qualifying for your State Pension.

At what profit do I start paying National Insurance?

Class 4 National Insurance starts once your profit goes above £12,570 for the year. Below that you pay no Class 4. Your Class 2 record is protected once profits reach £7,105, but that costs nothing.

Is National Insurance on top of income tax?

Yes. Class 4 National Insurance is charged in addition to income tax and is collected together with it through Self Assessment. A basic-rate sole trader effectively pays 20% income tax plus 6% Class 4 on profit in the £12,570–£50,270 band — 26% in total on that slice.

How and when do I pay it?

You pay Class 2 and Class 4 through your Self Assessment tax return. It's due with your income tax by 31 January after the end of the tax year — 31 January 2028 for the 2026/27 year — and it can be included in your payments on account.

Does National Insurance come off before or after expenses?

After. National Insurance is worked out on your profit — turnover minus your allowable business expenses — so every expense you claim reduces the Class 4 you pay as well as your income tax. Use the mileage and expenses calculator to make sure you're claiming everything.

More free tools

Full tax bill calculator →Income tax, Class 4 NI, payments on account and a monthly set-aside — your whole Self Assessment. Side hustle tax →Earning on the side? See the £1,000 trading allowance and what you actually owe. Sole trader vs limited →Would a company cut your NI and tax? Compare take-home both ways. Mileage & expenses →Claim the miles and costs that lower the profit your NI is charged on.

See the whole bill, not just the NI

Class 4 is one piece. What you actually pay on 31 January depends on your profit, any other income and your payments on account. Our Self Assessment Tax Estimator puts income tax and National Insurance together and tells you the monthly amount to set aside, so the bill never catches you out.

Self Assessment Tax Estimator 2026/27 — income tax, Class 4 NI, payments on account and a monthly set-aside, straight from your profit and expenses.
Freelance Day-Rate & Profit Calculator — the day rate you need to hit the take-home you want, after tax and NI.
Rental Property ROI & Yield Calculator — the real after-Section-24 return on a let.
Invoice Tracker & Log — auto paid/outstanding/overdue, with a chase list.

Excel and Google Sheets. Working formulas, not just formatting. Built and checked by us, with AI assistance, and every calculation verified.

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