National Insurance Gaps Calculator 2026/27
Find out whether paying voluntary National Insurance to fill gaps in your record is worth it — comparing the one-off cost against the lifetime boost to your State Pension.
Should You Fill Your National Insurance Gaps? The Core Maths
For most people with a genuine gap and room below 35 qualifying years, voluntary National Insurance is one of the highest-return uses of cash available anywhere — but it is not automatic, and a meaningful minority of people who pay end up wasting the money. The decision turns on three numbers: the cost per year, the pension boost per year, and how long you'll draw the pension.
The underlying arithmetic for a single Class 3 year:
Payback ≈ 2.5 years · 20-year lifetime gain ≈ £7,170 − £907 = £6,263 net
That return — roughly 39% a year in pension income against the outlay, continuing for life and rising each year with the triple lock — is why financial advisers so often flag filling gaps as a priority before other retirement saving. But the boost only applies if the year actually counts toward your figure, which is where the caveats below matter.
Class 2 vs Class 3 — the cost gap that changes everything
| Contribution class | Who it applies to | Approx cost / year (2026/27) |
|---|---|---|
| Class 3 (voluntary) | Most people filling gaps — employees, non-earners | ≈ £907 |
| Class 2 (voluntary) | Self-employed with profits below the small-profits threshold | ≈ £190 |
At the Class 2 rate, a year that adds £358.51 of annual pension pays for itself in well under one year of retirement — an exceptional return. Source: HMRC / GOV.UK voluntary NI rates; rates are set annually. Last verified May 2026.
When Filling Gaps is a Waste of Money
This is the information most pension pages skip — and it's the part that protects you from throwing money away. There are four situations where buying a year adds nothing:
Three Worked Scenarios
Scenario 1 — clear win: 3 useful gaps, 15 years from retirement
Scenario 2 — partial: only some years are useful
Scenario 3 — don't bother: reaching 35 anyway
2026 Rule Changes and Deadlines You Need to Know
The 6-year window is back
A temporary extension allowed people to fill gaps going all the way back to 2006 — but that window closed on 5 April 2025. The position has now reverted to the normal rule: you can generally only fill gaps from the last six tax years. If you have older gaps you didn't address before the deadline, they can no longer be filled in most cases. This makes acting on recent gaps more time-sensitive than it was.
Living abroad — Class 2 route closed from April 2026
From 6 April 2026, people living abroad can no longer pay the cheaper voluntary Class 2 rate for overseas periods — they must use Class 3, at roughly five times the cost. The eligibility criteria have also tightened: you now generally need either 10 years of continuous UK residence or 10 years of NI contributions (excluding voluntary payments from abroad), rather than the previous three-year test. Voluntary contributions paid before 6 April 2026 still count.
Rates are set annually
The Class 3 weekly rate is reviewed each year and does not always move predictably — it has been broadly flat in recent years. The figures here use an approximate 2026/27 Class 3 cost of £907 for a full year, but you should confirm the exact current rate on GOV.UK before paying, especially for the live tax year.
How to Fill a Gap — Step by Step
Frequently Asked Questions
How much does it cost to fill one National Insurance year?
For 2026/27, a full year through voluntary Class 3 contributions costs approximately £907 (around £17.45 a week). Self-employed people with low profits may qualify for the much cheaper Class 2 rate of roughly £190 a year. Older years are sometimes charged at the rate for the year you pay rather than the original year, so check before paying.
How long does it take to get my money back?
Each year bought adds about £358 a year to the full new State Pension for life. Against a Class 3 cost of around £907, that's a payback of under three years once your pension starts — and at the Class 2 rate, well under a year. After that, the extra pension is effectively free income for the rest of your life, rising annually with the triple lock.
Can I fill gaps from more than six years ago?
Generally no. The special extension allowing gaps back to 2006 ended on 5 April 2025, and the rules have reverted to the standard six-tax-year window. In limited circumstances older years can still be paid, but for most people only the last six tax years are now fillable.
Should I buy years or just keep working?
If you'll reach 35 qualifying years through normal employment before State Pension age, buying gaps is unnecessary — you'll get there for free. Filling gaps makes sense when you won't otherwise reach 35, or when you've already stopped working and are short of the full rate. The calculator above accounts for future working years automatically.
I was contracted out — will buying years still help?
Possibly, but it's less certain. If you were contracted out, your starting amount at April 2016 may already be at or near the full rate, in which case pre-2016 years won't help and only post-2016 years would. This is exactly why you must check your GOV.UK forecast — it shows whether each specific year increases your figure, accounting for any contracting-out deduction. See the State Pension Forecast Calculator for more on contracting out.
Does filling gaps affect anything other than my State Pension?
Qualifying years primarily build State Pension entitlement, but a sufficient NI record can also affect entitlement to some contributory benefits such as Maternity Allowance and bereavement benefits. For most people considering voluntary contributions, the State Pension boost is the main and decisive benefit.
Disclaimer: This tool provides an estimate for informational purposes only and does not constitute financial advice. Voluntary contribution rates and rules are set by HMRC and change annually. Always confirm via your GOV.UK State Pension forecast and the Future Pension Centre (0800 731 0175) before making any payment.