UK NI Top-Up Calculator
One Class 3 year costs ~£907 (2026/27), adds ~£342/year to State Pension — payback in ~3 years.
Voluntary Class 3 NI contributions can fill gap years and boost State Pension. Until April 2025 you could fill any year back to 2006; from April 2025 the limit is 6 years. Often one of the best-value pension purchases for those near retirement.
Worked examples
Buy 1 year: ~£907 cost. Adds ~£342/year to SP. Payback after 2.7 years.
Buy 5 years: ~£4,535 cost. Adds ~£1,710/year. Payback ~2.7 years.
Sources:
gov.uk voluntary NI
· retrieved 2026-05-14.
Frequently asked questions
Should everyone buy gap years?
Not always. If you'll reach 35 years before SPA from continued working/credit, no. Class 2 (self-employed cheaper) may be available retroactively. Use gov.uk official forecast first.
How long to break even?
About 3 years — one of the best-value moves available.
Can I buy years more than 6 back?
Usually only the previous 6 tax years. The 2025 deadline change affected longer windows.