Self-Employed National Insurance Calculator (2026/27)
Use our free self-employed National Insurance calculator to work out your Class 2 and Class 4 National Insurance on your profit.
Self-employed National Insurance: Class 2 and Class 4 explained
This self-employed National Insurance calculator covers Class 2 and Class 4 for sole traders, who pay National Insurance through their Self Assessment tax return.
Since April 2024, Class 2 is £0 for most self-employed people – the old flat weekly charge was scrapped for everyone with profits above the Small Profits Threshold. Class 4 is a percentage of your profits and remains payable.
National Insurance rates and thresholds (2026/27)
| Class 2 (weekly) | 2026/27 | 2025/26 |
|---|---|---|
| Below Small Profits Threshold | Under £7,105 | Under £6,845 |
| Voluntary rate (below SPT) | £3.65/week | £3.50/week |
| SPT to Lower Profits Threshold | £0 (NI credits earned) | £0 (NI credits earned) |
| Class 4 (annual) – unchanged for 2026/27 | Annual profit | Rate |
|---|---|---|
| Below Lower Profits Limit | Up to £12,570 | 0% |
| Main rate | £12,570 – £50,270 | 6% |
| Additional rate | Over £50,270 | 2% |
Source: HMRC – National Insurance rates and thresholds
Why the Class 2 reform matters
If your profit is between £7,105 and £12,570 (2026/27) you automatically build up a National Insurance record without paying anything – that record counts towards your State Pension.
If your profit is below £7,105 you get no record automatically. You can, however, pay Class 2 voluntarily at £3.65 a week (about £190 a year) to keep your record complete.
For many people that is the cheapest way to protect a year of State Pension entitlement – far less than a voluntary Class 3 contribution.
How to pay
Class 2 and Class 4 are paid together with Income Tax through Self Assessment, normally by 31 January following the end of the tax year. Register for Self Assessment on gov.uk if you have not already.
Self-employed National Insurance calculator FAQs
Do I pay NI if my profit is below £7,105 (2026/27)?
No Class 2 or Class 4 is due below the Small Profits Threshold, but you can pay Class 2 voluntarily at £3.65 a week to protect your NI record and State Pension.
Is paying voluntary Class 2 worth it?
It may be worthwhile if you need a qualifying year for your State Pension – check your State Pension record on gov.uk first. £3.65 a week (2026/27) is far cheaper than a Class 3 voluntary contribution, but if you already have enough qualifying years it may not be necessary.
What is the difference between Class 2 and Class 4?
Class 2 is a flat weekly rate tied to the Small Profits Threshold (now £0 for most); Class 4 is a percentage of profit between £12,570 and £50,270 (6%) and above £50,270 (2%).
When do I pay it?
With your Self Assessment bill, normally by 31 January after the tax year ends.
How is Class 4 calculated above £50,270?
6% on £12,570–£50,270 (£2,262) plus 2% on everything above £50,270.
Do I pay Class 4 after State Pension age?
No – if you are over State Pension age at the start of the tax year, you do not pay Class 4.