If your state pension forecast is below the full amount, filling gaps in your National Insurance record could be the best financial decision you ever make. Here’s how it works.
Read more: See our State Pension guide for a complete overview of this topic.
What Are NI Gaps?
A gap means a tax year where you didn’t pay enough National Insurance to count as a qualifying year for state pension purposes. Each qualifying year adds about £6.58/week to your new State Pension — up to the maximum of 35 years.
Common reasons for gaps:
- Unemployment without claiming benefits
- Living or working abroad
- Low earnings (below the Lower Earnings Limit of £6,500)
- Self-employment without paying Class 2 NI
- Career breaks for caring, studying, or travel
- Early retirement before State Pension age
How to Check for Gaps
- Go to gov.uk/check-national-insurance-record
- Sign in with Government Gateway
- Each year shows as “Full year”, “Year not full”, or “No record”
- Click individual years to see details and whether they can still be filled
Cost vs Benefit of Filling Gaps
This is the key calculation. Voluntary NI is remarkably good value:
| Factor | Amount |
|---|---|
| Cost of one year Class 3 NI (2026/27) | £907.40 |
| Extra weekly pension gained | £6.58 |
| Extra annual pension gained | £342 |
| Payback period | 2.7 years |
| Value over 20-year retirement | £6,840 |
| Return on investment | 754% |
Important: Check Before You Pay
Not every gap is worth filling. Voluntary contributions only increase your pension if:
- You have fewer than 35 qualifying years (including future years you’ll earn before State Pension age)
- You have at least 10 qualifying years in total (the minimum for any new State Pension)
- The year isn’t already counted through credits you haven’t claimed
How Many Years Do You Actually Need to Fill?
Calculate this before paying anything:
| Your situation | Qualifying years needed |
|---|---|
| Current qualifying years | Check NI record |
| Years until State Pension age | Calculate from your SP age |
| Expected future qualifying years | Years you’ll keep working/claiming credits |
| Total projected qualifying years | Current + expected future |
| Gap to fill | 35 minus total projected |
Example
Sarah, age 55, has 25 qualifying years. State Pension age is 67, so she has 12 more working years ahead.
- Current: 25 years
- Future: 12 years (assuming continued employment)
- Total: 37 years
- Gap to fill: 0 — she’ll exceed 35 years naturally
Sarah doesn’t need to fill any gaps because her future contributions will take her above 35 years.
Example 2
David, age 60, has 28 qualifying years. State Pension age is 67, so 7 more working years.
- Current: 28 years
- Future: 7 years
- Total: 35 years
- Gap to fill: 0 — he’ll just reach 35
But if David plans to retire at 63, he’d only get 31 years. Filling 4 gap years at £907 each (£3,628 total) would add £1,368/year to his pension — recouped in 2.7 years.
Which Gaps to Fill First
If you have multiple gaps, prioritise:
- Oldest years first — they have the earliest deadlines and often cost less (historical rates)
- Years with partial contributions — topping up a partial year costs less than a full year
- Years closest to expiring — the standard 6-year window means older gaps close first
Deadlines for Filling Gaps
| Tax year gap | Standard deadline | Notes |
|---|---|---|
| 2006/07–2017/18 | 5 April 2025 | Expired — special extension has now passed |
| 2018/19 | 5 April 2025 | Expired |
| 2019/20 | 5 April 2026 | Urgent — fill before April 2026 |
| 2020/21 | 5 April 2027 | Fill within the next year |
| 2021/22 | 5 April 2028 | |
| 2022/23 | 5 April 2029 | |
| 2023/24 | 5 April 2030 | |
| 2024/25 | 5 April 2031 |
How to Pay Voluntary NI
Step 1: Get Advice First
Call the Future Pension Centre on 0800 731 0175 (Monday–Friday, 8am–6pm). They will:
- Confirm which years will increase your pension
- Tell you exact costs for each year
- Provide a payment reference number
Step 2: Make Payment
| Payment method | Details |
|---|---|
| Bank transfer | Using the reference from Future Pension Centre |
| Direct Debit | For ongoing voluntary Class 3 payments |
| Cheque | Send to HMRC with payment reference |
| Online | Through your HMRC online account |
Step 3: Verify
Check your state pension forecast 6–8 weeks after payment to confirm your forecast has increased.
Special Cases
NI Credits You May Not Know About
Before paying voluntary NI, check whether you qualify for free NI credits:
| Credit type | Who qualifies |
|---|---|
| Child Benefit credits | Parents/carers of children under 12 |
| Specified Adult Childcare credits | Grandparents caring for grandchildren (if parent transfers) |
| Carer’s Credit | Caring 20+ hours/week for someone on certain benefits |
| Jobseeker’s credits | Registered as unemployed |
| Working Tax Credit | Some recipients get auto-credits |
Self-Employed Gaps
If you were self-employed and didn’t pay Class 2 NI, you can often fill these gaps at the cheaper Class 2 rate (£3.45/week vs £17.45/week for Class 3). Call HMRC to check eligibility.
Living Abroad
If you’ve lived abroad, you may be able to pay voluntary Class 3 NI while overseas, or use social security agreements between the UK and other countries to fill gaps. See our State Pension Abroad Rules guide.