Paying voluntary National Insurance to fill gaps: is it worth it?

Class 3 voluntary National Insurance costs £18.40 a week in 2026/27. What a full year buys, when it pays back, and when it adds nothing.

By Christopher Fagan. Published 1 October 2026. Checked against gov.uk 1 October 2026.

A gap year in your National Insurance record can usually be bought back. For most people who are short of 35 years, it is one of the best value purchases available. For some it adds nothing. The difference is in your forecast.

The numbers for 2026/27

Class 3 voluntary contribution: £18.40 a week, so £956.80 for a full year.
What a year adds: about 1/35th of the full new State Pension, £6.89 a week or about £358 a year, for life, rising with the triple lock.
Payback: under three years of receiving the pension. Live 20 years past State Pension age and a £957 payment returns over £7,000 before any increases.

Class 2 contributions, for the self employed, are much cheaper (£3.65 a week for 2026/27) and buy the same qualifying year.

When it adds nothing

You already have 35 qualifying years, or will have by State Pension age. Your forecast says "You cannot improve your forecast any further."
You were contracted out for years before 2016. Extra years may add less than 1/35th, or nothing, because of how the starting amount was calculated. Only the forecast or the Future Pension Centre can tell you.
You expect to get the years anyway through work or credits before you retire.

How far back you can go

You can normally pay for gaps in the last 6 tax years. The extended window to fill gaps back to 2006 closed on 5 April 2025. The two most recent years are charged at the rate for that year; older years at the current rate.

How to do it

Check your National Insurance record for gaps.
Check your forecast says you can improve it.
If you are more than a few years from State Pension age, call the Future Pension Centre before paying, to confirm which years will actually count.
Pay HMRC using the reference they give you. The forecast updates within a few weeks.

Sources

Information only, not financial advice. If a figure here and gov.uk ever disagree, gov.uk is right and we will fix it.