How much does it cost to fill a National Insurance gap?

A full missing year costs £956.80 at the 2026/27 Class 3 voluntary rate (£18.40 a week) — less if the year is only partly empty. Each completed year adds up to £6.89 a week to the new State Pension — about £358 a year, for life, rising with the triple lock. That means a bought year typically repays itself within three years of retirement. Self-employed? You may be able to pay Class 2 instead at a fraction of the cost — check before paying Class 3.

How do I check my NI record for gaps?

Free, in minutes: the HMRC app or your Personal Tax Account on GOV.UK shows every year of your record and flags incomplete ones, and the GOV.UK State Pension forecast shows what you're currently on track for. You need 35 qualifying years for the full new State Pension (£241.30 a week in 2026/27) and at least 10 for anything at all.

Should I pay to fill every gap?

No — two checks first. (1) Some gap years won't increase your pension at all (often because of past contracting-out, or because you'll reach 35 years anyway before State Pension age) — paying for those is money down the drain. Always check your forecast and ring the Future Pension Centre (0800 731 0175) to confirm WHICH years actually add money before paying. (2) Many gaps can be filled FREE with credits — see the free-credits list.

What free NI credits do people miss?

The big four: Child Benefit years (claiming Child Benefit for a child under 12 earns credits — even at the zero rate if a high earner opted out of payments); Specified Adult Childcare credits (grandparents and family members who look after a child under 12 while the parent works can have the parent's spare credit transferred — backdatable for years); Carer's Credit (caring 20+ hours a week); and credits that come automatically with UC, JSA, ESA or Maternity Allowance. Claiming a free credit beats buying the same year for £956.80.

What's the deadline for paying voluntary NI?

You can normally only fill gaps from the last 6 tax years — the window rolls forward every 6 April, so a year drops off the menu each spring (the special extended window back to 2006 closed in April 2025). If a valuable gap year is near the 6-year edge, that's the one to act on. And ignore any cold call about pension top-ups — HMRC and DWP don't sell by phone; do it only through GOV.UK.

NI gaps — buy missing years for £956.80, get £358/year for life (2026/27)

Step one: see your record — free, 5 minutes

The HMRC app or your Personal Tax Account on GOV.UK shows every tax year of your NI record and flags the incomplete ones.
The free GOV.UK State Pension forecast shows what you’re on track for. You need 35 qualifying years for the full new State Pension (£241.30/week in 2026/27) and at least 10 for anything.
Decades from retirement with a few gaps? You may simply fill the 35 naturally — which is exactly why you check before paying.

Step two: claim the free fills

Before spending £956.80 on a year, check whether Britain owed you that year for free:

Child Benefit years — claiming for a child under 12 earns NI credits automatically. High earner who opted out of payments? Claim at the zero rate — the credits still count.
Specified Adult Childcare credits — grandparents (and other family) who mind a child under 12 while the parent works can have the parent’s spare credit transferred to them — backdatable for years. One of Britain’s least-claimed entitlements.
Carer’s Credit — caring 20+ hours a week protects the year even when Carer’s Allowance isn’t payable.
Benefit-linked credits — UC, JSA, ESA and Maternity Allowance all carry credits automatically; check those years actually show as complete.

A free credit beats a bought year, every time Each route above fills the same gap the £956.80 payment would — for nothing. Work through them first; many “gaps” turn out to be unclaimed credits.

Step three: buy only the years that count

Route	2026/27 cost	Who
Class 3 voluntary	£18.40/week — £956.80 a full year	Most people filling gaps
Class 2 voluntary	A small fraction of Class 3 — check the current rate	Self-employed (incl. some past self-employed years & some working abroad)

Ring the Future Pension Centre first — 0800 731 0175. Some gap years won’t increase your pension at all (old contracting-out, or you’ll hit 35 years anyway). They’ll tell you exactly which years add money. This call is the difference between a brilliant purchase and a wasted one.
Pay through the GOV.UK voluntary-NI service only — it takes payment and allocates it to the right years.
Mind the rolling window: you can normally only fill the last 6 tax years, and one drops off every 6 April (the special window back to 2006 closed in April 2025). If a valuable year is near the edge, do that one first.

Two traps (1) Paying for dead years — never buy without the forecast + Future Pension Centre confirmation. (2) Cold calls — HMRC and the DWP never phone selling pension top-ups; anyone who does is a scammer. Everything happens on GOV.UK or numbers you dialled yourself (check anything suspicious).

Do this now

Tonight, free: open the HMRC app → NI record, and run the State Pension forecast. Note any incomplete years and which free credits above might cover them.

Gaps left that matter? 0800 731 0175 before paying a penny — then pay only the confirmed years, oldest valuable one first.

Worked example — the honest maths One bought year: £956.80 once → +£6.89/week = £358.28/year of State Pension, every year of retirement, uprated by the triple lock. Live 20 years past pension age and that single year returns roughly £7,000+ on a £956.80 outlay. Few investments in Britain come close — which is exactly why checking it’s a year that counts matters so much.

Source verification Primary source: GOV.UK voluntary National Insurance + HMRC 2026/27 rates + MoneyHelper · gov.uk/voluntary-national-insurance-contributions. Last verified 11 June 2026. Confidence: High — published rates; per-year value capped at £6.89/wk (arithmetic: £241.30 ÷ 35). Key facts: Class 3 £18.40/wk = £956.80/yr (2026/27) · +£6.89/wk (£358/yr) per qualifying year · 6-year rolling window · free credits (CB years, Specified Adult Childcare, Carer’s Credit, benefit-linked) · Future Pension Centre 0800 731 0175 check first. Scope: UK-wide.

NI gaps — common questions

How much does a missing year cost to fill?

£956.80 at the 2026/27 Class 3 rate (£18.40/week) — less for partly filled years, and far less via Class 2 if you're self-employed. Each bought year adds up to £6.89/week (£358/year) of pension for life.

How do I check my record?

Free in the HMRC app or your Personal Tax Account (year-by-year record with gaps flagged) plus the GOV.UK State Pension forecast. 35 years = full pension; 10 = minimum.

Should I fill every gap?

No — claim free credits first (Child Benefit years, grandparent childcare credits, Carer's Credit, benefit-linked), then ring the Future Pension Centre (0800 731 0175): some years add nothing and they'll tell you which ones count.

What's the deadline?

Normally the last 6 tax years, with one dropping off every 6 April — so a valuable year near the edge is the one to do first. The extended window to 2006 closed in April 2025.

Someone phoned offering a pension top-up — legit?

No — HMRC and the DWP never sell top-ups by phone. It's a scam pattern; hang up and use GOV.UK directly.

Sources: Voluntary contributions, the 6-year window and payment routes · GOV.UK voluntary NI. Class 3 rate £18.40/wk (2026/27) · HMRC NI rates. Per-year value up to £6.89/wk · arithmetic on the 2026/27 full new State Pension (£241.30 ÷ 35, as verified for the State Pension guide) + MoneyHelper + Which?. Free credits (Child Benefit, Specified Adult Childcare, Carer’s Credit) · GOV.UK NI credits. Check-first · Future Pension Centre 0800 731 0175. SortedUK is not HMRC/DWP and this is general information, not financial advice. Last reviewed: 11 June 2026.

Gaps in your NI record — the £358-a-year fix (and the free one first).

Step one: see your record — free, 5 minutes

Step two: claim the free fills

Step three: buy only the years that count

NI gaps — common questions

Five minutes in the HMRC app. Decades of difference.