Hundred SummersVoluntary NI contributions: the best deal in UK finance, checked honestly
Each qualifying year bought adds 1/35th of the full new State Pension (about £358 a year, for life, inflation-protected) for a one-off payment of roughly £900. This calculator shows the after-tax breakeven. Your figures never leave your browser.
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Worked example
Computed when this page was built by the same engine that runs the calculator above, so the figures below and the live tool can never disagree. Change any input above to see your own.
| Inputs | |
|---|---|
| Missing years bought | 3 |
| Cost per year (Class 3) | £957 |
| State Pension age | 66 |
| Basic-rate taxpayer in retirement | Yes |
| Results | |
|---|---|
| Total cost | £2,871 |
| Extra State Pension a year, gross | £1,076 |
| After tax | £861 |
| Paid back after | 3.3 years (age 69) |
| Gain by 90 | £17,793 |
The next question
Should I defer my State Pension? →State Pension deferral calculator
Or answer it with everything else: the full Hundred Summers plan connects your pay, pensions, savings, property, tax and spending year by year, and stress-tests them across 500 simulated market histories.
Read the guides
- Optimising your plan: every lever, which ones apply to you, and how they fit together →The overview of every way a UK retirement plan can be improved (tax while you work, where your savings go, how you draw it down and what your estate pays) with a decision tree that finds the levers relevant to you, the combinations that pull against each other, and how to test them in Hundred Summers. Each lever links to the guide that goes deeper. Education, not advice.
- Deferring your State Pension: the honest breakeven →The permanent ~5.8% a year uplift for waiting, the income you give up, the roughly age-83 breakeven, and the tax angle that often matters more: the statutory mechanics, worked through honestly.
- Buying National Insurance years: the best deal in UK finance →Each Class 3 year costs about £960 and adds ~£359 a year of State Pension for life: a three-year breakeven. Who it helps, who it can't, and the checks to run before paying HMRC anything.
Why this is usually exceptional value
The full new State Pension needs 35 effective qualifying years of National Insurance. Finish short and each missing year permanently costs you 1/35th of the pension, and each year bought back permanently restores it. Pay roughly £900 once, receive ~£358 a year (rising with the pension) for the rest of your life: even taxed at basic rate, the payback is around three years. Almost nothing legal beats it.
The checks that come first
Buying a year does nothing if you'd reach 35 effective years anyway through future work: a 45-year-old with 25 years and 20 working years ahead needs no top-up. And some records are complicated by pre-2016 contracting-out, where an extra year genuinely adds nothing. So: check your State Pension forecast and NI record on gov.uk, and for anything unclear ring the Future Pension Centre before paying. Normally you can go back six tax years.
The full Hundred Summers plan models your qualifying years, future working years and gap-filling inside your whole retirement picture, and its deferral calculator covers the other State Pension decision.