In August 2026, HMRC began issuing targeted letters to approximately 800,000 self-employed taxpayers, alerting them to gaps in their National Insurance contribution records. If you receive one of these letters, it does not mean you have done anything wrong. It is an administrative notification — HMRC alerting you to a shortfall that could reduce your State Pension entitlement if left unaddressed.
But the consequences of ignoring it can be significant. For every year of NI gaps that goes unfilled, you may receive a smaller State Pension in retirement. And the window to fill some of those gaps voluntarily is not unlimited.
This article explains what the letters mean, how to check your own NI record whether or not you have received a letter, and what it costs to fill gaps — and whether it is worth doing.
Why National Insurance Gaps Matter
The UK State Pension is built on a system of qualifying years. To receive the full new State Pension — currently £11,502.40 per year — you need 35 qualifying years of National Insurance contributions or credits. To receive any State Pension at all, you need at least 10 qualifying years.
A qualifying year is one in which you paid enough NI contributions — either through employment, self-employment, or NI credits (which apply automatically in some circumstances, such as when you are receiving Child Benefit for a child under 12).
A gap year is one in which you fell below the qualifying threshold. This happens most commonly when self-employed profits fall below the Small Profits Threshold (currently £6,845 per year), when someone takes time out of work without claiming relevant benefits, or when a person was self-employed but chose not to pay voluntary contributions at the time.
For someone with a 5-year gap in their record, the impact on their State Pension could be a reduction of nearly £1,644 per year — every year for the rest of their life. Over a 20-year retirement, that is more than £32,000 of lost income.
Who Is Receiving the Letters
HMRC's August 2026 exercise is specifically targeting self-employed individuals. The reasons are structural: employees typically have their NI contributions deducted automatically through PAYE and gaps are rare. Self-employed people, on the other hand, pay NI through the Self Assessment system, and gaps arise more easily — particularly in years of low profit, career transitions, or periods of irregular working.
The letters HMRC is sending are not penalty notices or demands. They are notifications setting out which years in your NI record show as gaps and inviting you to consider whether to fill them through voluntary Class 3 NI contributions.
Even if you have not received a letter, this is a good moment to check your own record. HMRC's online NI record checker — available through your Government Gateway account — shows your contribution history year by year and flags any gaps. Checking takes ten minutes and could save you tens of thousands of pounds over your retirement.
What Voluntary NI Contributions Cost
Where gaps exist in your record, you can fill them by paying voluntary Class 3 NI contributions. The current rate for 2026/27 is £17.45 per week, meaning a full year of Class 3 contributions costs approximately £907.
In return, filling a gap adds one qualifying year to your State Pension record, increasing your annual State Pension by approximately £329 per year (one thirty-fifth of the full new State Pension of £11,502.40).
The payback calculation is straightforward: at £907 to buy a year, and £329 per year of additional pension, you recover the cost in just under three years of retirement. Given average life expectancy, most people who fill a gap will receive many multiples of what they paid in voluntary contributions.
There is an important deadline dimension. The normal rule is that you can only pay voluntary contributions for the six tax years immediately preceding the current one. In 2026/27, that means you can normally pay back to 2020/21. Gaps before that are permanently closed — you cannot buy them back.
However, there is a temporary extension for filling gaps from the 2006/07 tax year onwards that has been available since April 2023. The deadline for using this extended window was repeatedly extended and is currently confirmed through to 5 April 2027. This means there is still time — but only until April 2027 — to fill gaps going back to 2006/07 at the Class 3 rate, rather than losing those years permanently.
If you have significant NI gaps from the period 2006/07 to 2020/21, the window to act is now, not later.
Is It Always Worth Filling a Gap?
For most people, yes — the arithmetic strongly favours filling gaps where possible. But there are situations where it is not straightforward, and taking advice is worthwhile.
If you are already projected to receive the full new State Pension — 35 qualifying years already secured — filling additional gaps makes no difference to your State Pension. The State Pension does not increase beyond the full rate regardless of how many qualifying years you accumulate above 35.
If you have a workplace or private pension that will provide a substantial retirement income, the marginal value of additional State Pension income may be lower in your tax planning overall — though the State Pension remains valuable as a guaranteed, inflation-linked income that requires no investment risk.
If you are not yet close to State Pension age and have enough working years ahead to accumulate the required 35 years without buying back gaps, voluntary contributions may be unnecessary. Check your State Pension forecast — also available through your Government Gateway account — before committing.
The key question to answer before paying voluntary contributions is: will this additional qualifying year actually increase my State Pension? Your online forecast will show whether you are on track for the full pension or whether gaps will reduce it.
The Practical Steps to Take Now
Check your NI record through your Government Gateway account at gov.uk. The record will show each tax year from the date you started working, whether it is a qualifying year or a gap, and whether the gap can still be filled.
Request a State Pension forecast. This shows what you are currently projected to receive and whether filling gaps would increase that figure.
If gaps exist for years between 2006/07 and 2020/21 that would increase your State Pension, consider paying the voluntary contributions before April 2027 while the extended deadline applies.
Contact HMRC's Future Pension Centre on 0800 731 0175 if you need help understanding your record. They can confirm whether filling a specific gap would increase your pension and explain the payment process.
If your situation is complex — particularly if you have periods of self-employment, overseas working, or career breaks — speak to your accountant before paying contributions. CoreAcc Accountants can help you review your NI record in the context of your wider financial planning.
A Note for Directors and Business Owners
Directors of limited companies who pay themselves a low salary — typically around the personal allowance threshold of £12,570 — should be aware that their NI record depends on their salary level relative to the Lower Earnings Limit, which is £6,500 per year in 2026/27.
A salary at or above the Lower Earnings Limit secures a qualifying year without any NI contributions actually being paid — there is a notional credit. A salary below the Lower Earnings Limit does not secure a qualifying year. Directors who have paid themselves a salary between £6,500 and £12,570 will typically have a qualifying year credited even though no employee NI is deducted.
Directors who have paid themselves a salary below £6,500 in any year — for example, in a start-up year or a low-profit year — may have an NI gap for that year. Check your record.
If you have received an HMRC letter about NI gaps, or want to review your NI record and State Pension position, contact CoreAcc Accountants today.
CoreAcc Accountants is an ACCA-accredited firm of Chartered Certified Accountants. This article was published on 13 August 2026 and reflects HMRC guidance in force at that date. It does not constitute financial advice. Always seek specific advice for your individual circumstances.
