Self-Employed National Insurance Calculator UK 2025/26 — Class 2 & Class 4
Self-employed people pay two types of National Insurance: Class 2 (a flat weekly amount that protects your State Pension and benefits entitlement) and Class 4 (a percentage of profits above the Lower Profits Limit). From April 2024 the rules changed significantly — Class 2 is now treated as effectively zero for most people but voluntary contributions are still important.
2025/26: Class 2 NIC credited automatically if profits ≥£12,570 (no cost). Class 4: 6% on £12,570–£50,270 profits, 2% above. Both paid via Self Assessment. Register for Self Assessment at gov.uk by 5 October after the tax year. Voluntary Class 2 (£3.45/week) protects State Pension if profits below threshold.
Class 2 and Class 4 NIC — 2025/26 Rates
| Class | Rate | Threshold | Benefit entitlement |
|---|---|---|---|
| Class 2 | £0 (auto-credited if profits ≥£12,570) | Lower Profits Threshold: £12,570 | State Pension, ESA, maternity allowance |
| Class 2 (voluntary) | £3.45/week (£179.40/year) | Profits below £12,570 | As above — buys qualifying year |
| Class 4 | 6% | £12,570 – £50,270 profits | None (pure tax) |
| Class 4 upper | 2% | Above £50,270 | None |
Why Voluntary Class 2 Matters
The Class 2 changes from April 2024 mean that those earning above £12,570 get their NIC contributions automatically — this is free and counts towards the State Pension. For those earning below the threshold, paying £3.45/week voluntarily buys a qualifying year for £179.40. With the full new State Pension at £11,502/year (2025/26), each qualifying year is worth approximately £329/year for life. The payback period on voluntary Class 2 is less than 7 months — making it one of the best investment returns available.
Reducing Your NIC Through Pension Contributions
Unlike employees who get NIC relief on pension contributions through salary sacrifice, self-employed people pay NIC on their trading profits before pension contributions are deducted. However, pension contributions still reduce your income tax bill as they reduce adjusted net income. There is no Class 4 NIC relief for pension contributions — this is one of the less favourable aspects of self-employment compared to employment for higher earners.
Frequently Asked Questions
You pay both Class 1 NIC (as an employee) and Class 4 NIC (on self-employed profits). However, HMRC has rules to prevent you paying more than the maximum overall NIC liability. The annual maximum is calculated by HMRC and if you overpay (common for those with multiple income sources), you receive a refund. Class 2 NIC is now effectively automatic if profits exceed the threshold.
You must register for Self Assessment by 5 October following the end of the tax year in which you became self-employed. Failure to register can result in a £100 penalty plus penalties for late filing (after 31 January) and late payment. If you have been self-employed for several years without registering, HMRC will generally want tax for the last 4 years plus interest. It is always better to come forward voluntarily — you can use the HMRC Voluntary Disclosure process for historic tax debts.