What you need to know: Class 2 vs Class 3 NI : which to pay
Quick answer: For voluntary buyback of NI years: Class 2 costs £3.65/week (£189.80/year) but is only available for tax years when you were self-employed and earning below the small profits threshold. Class 3 costs £18.40/week (£956.80/year, 2026/27) but is available to almost anyone with gaps. Both add the same amount to State Pension —…
Key points:
- Tax years when you were registered as self-employed.
- Years when your self-employment profits were below the small profits threshold (the level that triggered compulsory Class 2 — now abolished for current years from April 2024).
- Tax years 2015/16 to 2023/24 are the typical eligibility window for retrospective Class 2 buyback.
For voluntary buyback of NI years: Class 2 costs £3.65/week (£189.80/year) but is only available for tax years when you were self-employed and earning below the small profits threshold. Class 3 costs £18.40/week (£956.80/year, 2026/27) but is available to almost anyone with gaps. Both add the same amount to State Pension — about £329/year. Use Class 2 if available (5x cheaper); fall back to Class 3 for non-self-employed gap years.
Class 2 — the cheap option (when available)
Class 2 NI was historically paid by self-employed people at a low flat rate. For voluntary buyback, Class 2 applies to:
- Tax years when you were registered as self-employed.
- Years when your self-employment profits were below the small profits threshold (the level that triggered compulsory Class 2 — now abolished for current years from April 2024).
- Tax years 2015/16 to 2023/24 are the typical eligibility window for retrospective Class 2 buyback.
From April 2024, Class 2 NI was abolished prospectively — current self-employed people no longer pay it. But voluntary historic buyback at Class 2 rates is still permitted for prior years.
Class 3 — the universal option
Class 3 NI is available to nearly anyone with a UK NI record. There's no eligibility test based on employment — you can fill any year. At £956.80/year, it's more than 5x the cost of Class 2 but still excellent value relative to the State Pension increase.
Same outcome — different cost
| Class 2 | Class 3 | |
|---|---|---|
| Cost per year | £179.40 | £959.40 |
| State Pension increase per year | £329 | £329 |
| Break-even (months of retirement) | ~7 months | ~35 months |
| 20-year retirement return | ~37x | ~7x |
Both are exceptional investments. Class 2 is staggeringly good when available.
Eligibility for Class 2 buyback
You can buy back Class 2 for a tax year if all four conditions are met:
- You were ordinarily resident in the UK during that tax year.
- You had self-employed work during that year — even occasional or part-time.
- Your self-employment profits were below the small profits threshold (varies by year — around £6,725 in 2023/24).
- You haven't already paid voluntary contributions for that year.
If you were a regular salaried employee with no self-employment during the gap year, Class 2 is not available. Use Class 3.
Worked example — mixed-history individual
Self-employed 2010–2015, salaried 2016–2024, now wants to fill 3 gap years (2011, 2013, 2018)
| Gap year 2011 — was self-employed, profits below threshold | Class 2 eligible: £179 |
| Gap year 2013 — was self-employed, profits below threshold | Class 2 eligible: £179 |
| Gap year 2018 — was salaried (career break) | Class 3 only: £959 |
| Total cost to fill 3 years | £1,317 |
| State Pension increase | £987/year (3 × £329) |
If all three were filled at Class 3 rates, it would cost £2,877. The mixed approach saves £1,560 while achieving identical State Pension increase.
How to confirm Class 2 eligibility
Call HMRC's Future Pension Centre (0800 731 0175). They have your full NI history and can confirm year-by-year which rate applies.
If HMRC's records show "self-employed" for the gap year, Class 2 is usually available. If the records show "no employment" or "unemployed," Class 3 is the only option.
For very old gap years (pre-2006), the records may be incomplete. HMRC will guide you on what's recoverable.
The April 2027 deadline
The same April 2027 deadline applies — both Class 2 and Class 3 buyback for 2006–2018 must be done by 5 April 2027. After that, only the last 6 tax years can be filled at either rate.
Sources and methodology
Class 2 and Class 3 NI rules are in the Social Security Contributions and Benefits Act 1992 (as amended). See HMRC's voluntary NI rates. For personalised analysis, see the Class 3 calculator. The methodology page documents sources.
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