How many missing years do you want to fill?

Only count years your GOV.UK forecast says would increase your pension. You can usually go back six tax years.

Which class can you pay? Class 3 (£18.40 a week): most people with gaps Class 2 (£3.65 a week): self-employed with low profits, some people working abroad

Weekly rate you will pay (£)

Filled in for 2026/27. Change it if HMRC quotes you a different rate for an older year.

Your current State Pension forecast, a week (optional)

From the GOV.UK forecast. We use it to stop at the full rate of £241.30.

Income tax on your State Pension

Years you expect to receive your State Pension

For illustration only. Nobody knows this for sure.

How this calculator works

Each qualifying year on your National Insurance record adds one thirty-fifth of the full new State Pension, until you reach the full amount. In 2026/27 that is £241.30 ÷ 35 = £6.89 a week, or about £359 a year.

Cost = weekly rate × 52 × number of years
Extra pension a year = £6.89 × 52 × number of years, capped at the full rate
Payback = cost ÷ (extra pension a year after your income tax)

For one Class 3 year: £956.80 ÷ £359 = about 2 years 8 months before tax, or about 3 years 4 months if you pay 20% tax on it. A Class 2 year costs £189.80 and pays back in about 6 months.

Before you pay anything

Check your forecast. Check your State Pension forecast shows your gaps and whether filling each one would raise your pension.
Check for free credits. If you were claiming Child Benefit for a child under 12, caring for someone or on certain benefits, you may be due National Insurance credits instead of paying.
Know the deadline. You can usually pay for the past six tax years. Gaps in 2020/21 can be filled until 5 April 2027.
Think about Pension Credit. If you expect to claim it, extra State Pension may reduce it, so you could gain little.

Our guide should you pay voluntary National Insurance? covers who can pay each class and the cases where paying is wasted money.

What the calculator doesn't cover

People who reached State Pension age before 6 April 2016. They are on the old basic State Pension, and voluntary contributions can't increase it.
Protected payments and contracted-out deductions from before 2016. Your forecast already reflects them; follow what it says.
Future increases to the State Pension, which make the payback faster than shown.
Scotland's different income tax bands.

Sources and assumptions

This calculator gives an estimate based on the rules shown. It is not personal financial advice. Check your own figures with your pension provider, GOV.UK or a regulated adviser before you act.