Class 2 & 4 National Insurance calculator
Self-employed National Insurance is mostly Class 4, charged on your profits. This shows the Class 4 due and confirms the Class 2 position for the year.
How self-employed National Insurance works
There are two classes. Class 4 is the main one, charged as a percentage of profits: 6% on the slice between £12,570 and £50,270, then 2% on anything above £50,270. Nothing is charged on profits below £12,570. Class 2 used to be a flat weekly charge, but since 2024/25 there is nothing to pay if your profits are above the Small Profits Threshold, and the year still counts towards the State Pension.
Below the Small Profits Threshold of about £7,105, Class 2 becomes voluntary. Paying it, at a low weekly rate, keeps the year on your record, which can matter for the State Pension and some benefits. That is a personal decision, so it is left out of the headline figure.
Worked example
On £40,000 of profit, the Class 4 band that counts is £12,570 to £40,000, so 6% of £27,430 is £1,646. The profit does not reach £50,270, so there is no 2% band, and Class 2 is treated as paid at £0. The National Insurance bill is therefore £1,646, on top of income tax. A profit above £50,270 would add 2% on the excess.
Both rates in one place
| Band | Rate |
|---|---|
| Profit up to £12,570 | No Class 4 |
| £12,570 to £50,270 | 6% |
| Above £50,270 | 2% |
| Class 2 (profit above £7,105) | £0, treated as paid |
Common questions
What National Insurance do the self-employed pay?
Class 4 on profits, at 6% between £12,570 and £50,270 and 2% above. Class 2 is a separate flat charge, but from 2024/25 there is nothing to pay for most people: if your profits are above the Small Profits Threshold of £7,105 the year still counts for the State Pension, treated as paid.
How much Class 4 will I pay?
On £40,000 of profit, Class 4 is about £1,646. That is 6% on the profit between £12,570 and £50,270. Nothing is due on the first £12,570, and the 2% band only starts once profit passes £50,270.
Do I still pay Class 2 National Insurance?
Not if your profits are above the Small Profits Threshold of £7,105, where it is treated as paid at £0. If your profits are below that you can pay Class 2 voluntarily to keep the year on your National Insurance record, which protects the State Pension and some benefits.
Is Class 4 the same as income tax?
No, they are separate. Class 4 National Insurance is charged on top of income tax on the same profits, and both are collected through Self Assessment. This tool covers the National Insurance only; use the Self Assessment estimator for the full bill.