HMRC has acknowledged a long-running State Pension tax calculation error that affected some PAYE, Self Assessment and Simple Assessment records. The issue concerns how taxable State Pension figures were calculated after annual uprating, not a claim that every pensioner’s entire State Pension was wrongly taxed.
The practical meaning is important but should be read carefully. HMRC says an incorrect State Pension figure was used in some tax calculations, and in 2024/25 around 1.4 million PAYE pensioners paid too much tax because of the issue.
It also said up to 955,000 Self Assessment pensioners and around 760,000 Simple Assessment pensioners may have had incorrect figures used, although the latter two estimates are upper limits.
Last checked: 10 July 2026
Key highlights:
- The PAYE issue dates back to 2010/11.
- Self Assessment pre-population was affected from 2015/16.
- Simple Assessment calculations were affected from 2016/17.
- The error relates to one week of State Pension uprating, not the whole annual pension.
- Average annual overpayments for many basic-rate taxpayers were estimated in pounds, not hundreds of pounds.
- Not every State Pensioner is automatically due a repayment.
- Pensioners who are concerned should check official tax records and use normal HMRC routes.
What Does HMRC Admitted Overtaxing Millions of State Pensioners Since 2010 Actually Mean?
It means HMRC accepted that some taxable State Pension figures used in tax calculations were wrong. The error arose where systems used 52 weeks at the current year’s State Pension rate, instead of the usual split of one week at the previous year’s rate and 51 weeks at the current year’s rate.
The official letter includes the direct statement:
“I apologise for this error and especially to those pensioners who have been affected.”
However, this does not mean every pensioner was overcharged or that every affected record leads to a refund. HMRC said some differences fall within administrative tolerances, meaning very small overpayments may not have been automatically repaid and small underpayments may not have been pursued.
Why Did HMRC Overcharge Some Pensioners Through State Pension Tax Calculations?
State Pension is taxable where a person’s total taxable income is above their Personal Allowance.
The State Pension can form part of total annual income, alongside private pensions, employment, taxable benefits, savings, property income or other taxable income. Claimants can check the rule through the official pension tax guidance page.
The error came from the way annual State Pension increases were reflected in tax calculations. Because State Pension is normally paid in arrears, most pensioners’ taxable State Pension for a tax year should include one week at the previous year’s rate and 51 weeks at the new rate. Some systems instead used 52 weeks at the new rate, overstating taxable income slightly.
Simple calculation principle:
| Correct approach | Incorrect approach | Why it matters |
| 1 week at old rate + 51 weeks at new rate | 52 weeks at new rate | Taxable State Pension may be overstated |
| Applies to most pensioners after uprating | Used in some system calculations | May create a small tax overpayment |
| Difference is taxed at marginal rate | Difference may vary by pension type | Higher-rate taxpayers may see different results |
This is why the issue can be small for one person but significant when repeated across millions of pensioner tax records.
Who Could Be Affected by the HMRC Pensioner Income Tax Error?
The issue could affect pensioners whose State Pension figure was used in PAYE, Self Assessment or Simple Assessment calculations. Pensioners with only State Pension income below the Personal Allowance may not have paid tax, so the practical effect depends on total income and tax route.
Groups most likely to check records:
- PAYE pensioners whose tax is collected through a private pension, employment income or another PAYE source.
- Self Assessment taxpayers whose online return may have used a pre-filled State Pension figure.
- Simple Assessment taxpayers who received a tax calculation bill.
- Pensioners with private pensions, rental income, savings income or employment income alongside State Pension.
The key risk is not simply receiving State Pension. The risk is whether an incorrect State Pension figure affected the amount of tax collected, repaid or calculated.
How Far Back Does the HMRC State Pension Tax Error Go?
The HMRC State Pension tax error dates back to 2010, but the timeline differs depending on how a pensioner’s tax was assessed. The earliest confirmed issues relate to PAYE, while Self Assessment and Simple Assessment were affected in later years.
PAYE Records From 2010/11
The PAYE issue is linked to a system change introduced in 2010, which resulted in incorrect State Pension figures being used in some end-of-year tax reconciliations from 2010/11.
HMRC estimates that around 1.4 million PAYE pensioners overpaid tax in 2024/25, although its detailed review has mainly focused on the 2021/22 to 2024/25 tax years because of data and record retention limitations.
When Were Other Tax Routes Affected?
The error did not affect all HMRC tax systems at the same time. Instead, different tax routes were impacted in different years:
- Self Assessment: Affected from 2015/16.
- Simple Assessment: Affected from 2016/17.
Understanding these different timelines is important because it helps explain why the reported tax error did not apply to every pensioner or every HMRC tax calculation from 2010 onwards.
How Many UK Pensioners May Have Paid Too Much Tax?
HMRC said the State Pension population in 2024/25 was around 13.3 million, including around 11.5 million in PAYE only and around 1.9 million in Self Assessment.
Within that, 1.4 million PAYE pensioners were estimated to have paid too much tax in 2024/25 because of the issue.
Estimated scale in 2024/25:
| Tax route | HMRC estimate | Important caution |
| PAYE | Around 1.4 million paid too much tax | Based on latest reconciliation outcome |
| Self Assessment | Up to 955,000 may have had an incorrect figure | Upper-limit estimate |
| Simple Assessment | Around 760,000 may have had an incorrect figure | Upper-limit estimate |
| Total State Pension population | Around 13.3 million | Not all were overtaxed |
The word “millions” is therefore relevant to the scale of potentially affected records, but each category needs to be read with its own caveats.
How Much Money Could State Pensioners Have Overpaid?
For many basic-rate taxpayers, HMRC’s estimate suggests the average annual overpayment was small. Between 2021/22 and 2024/25, it estimated an average annual overpayment of £1.76 for a person receiving the full basic State Pension and £2.30 for a person receiving the full new State Pension.
That does not mean every individual figure is the same. The amount may vary depending on whether the pensioner receives a full or partial State Pension, whether they receive enhancements, and whether they pay basic, higher or additional-rate tax.
Why the amount may vary?
- A higher marginal tax rate can increase the tax effect.
- A partial State Pension can reduce the difference.
- Additional State Pension or enhancements may change the calculation.
- Tax records may have been corrected manually in some cases.
- Some differences may fall within administrative tolerances.
The financial value for many individuals may be modest, but the issue remains serious because of its duration, the number of affected people and the importance of accuracy for pensioners on fixed incomes.
What Should Pensioners Check If They Think HMRC Overcharged Them?
Pensioners should start with records, not assumptions. The most useful documents are likely to be P800 letters, Simple Assessment letters, Self Assessment returns, PAYE coding notices, DWP State Pension letters and Personal Tax Account information.
Which Tax Records Should Pensioners Review?
Start by checking documents that show both your tax calculation and State Pension income, including:
- P800 or Simple Assessment letters
- Self Assessment tax returns
- PAYE tax coding notices
- DWP State Pension entitlement letters
- Personal Tax Account records
Compare the State Pension figure shown in these records with the amount you were entitled to receive for the relevant tax year.
When to Contact HMRC?
If you believe the tax calculation is incorrect, contact HMRC after reviewing your records. In some cases, HMRC may issue a P800 or Simple Assessment explaining whether you are due a refund or need to pay additional tax.
The tax overpayment and underpayment guidance also explains what to do if you have not received a letter or believe your tax calculation is incorrect.
What Self Assessment Taxpayers Should Consider?
Self Assessment taxpayers should review whether the correct State Pension amount was entered on their return and whether it can still be amended if necessary. If a refund may be due, the official tax refund checking tool can help you check your eligibility before contacting HMRC or seeking regulated professional advice for more complex cases.
Before sharing personal or financial information, make sure you are dealing with HMRC or a trusted professional adviser rather than an unverified refund company.
Why Does This HMRC Pension Tax Error Matter Even If Some Overpayments Were Small?
The HMRC State Pension tax error matters because it affects confidence in how pension income is calculated and corrected. Although many overpayments were relatively small, the issue continued for several years and affected a large number of pensioner tax records.
For many pensioners, even small overpayments matter because they rely on fixed incomes and may not regularly check their tax calculations. The error also created uncertainty for families, advisers and taxpayers who expect HMRC records to be accurate.
Why the Issue Still Matters?
- It affected many pensioners, including those less familiar with online tax services.
- It involved State Pension income, which many assume is recorded correctly.
- It may have affected PAYE, Self Assessment and Simple Assessment taxpayers.
- It raises questions about HMRC’s data checks and system accuracy.
- It highlights the need for clear guidance on refunds and corrections.
Overall, the issue is about more than the value of individual overpayments. It also highlights the importance of accuracy, transparency and trust in the UK tax system.
What Happens Next for HMRC, Pensioners and Public Trust?
HMRC said it would deliver a solution in summer 2026 to correct future tax calculations, including 2025/26 outcomes for PAYE and Simple Assessment and returns already filed by Self Assessment taxpayers. It also commissioned an internal audit to examine the history and causes of the issue and said it would report back later in 2026.
For pensioners, the practical message is measured: do not panic, but do check records if there is reason to believe the State Pension figure used for tax was wrong. For HMRC, the public trust issue is wider. A small annual tax error can become a major confidence problem when it lasts for years and affects older taxpayers, many of whom live on fixed or limited incomes.
The next important developments will be the correction process, customer guidance, audit findings and any further clarification on repayments for earlier years.
Conclusion
HMRC admitted overtaxing millions of State Pensioners since 2010, but the issue should be understood carefully. It relates to specific State Pension tax calculation errors, not automatic refunds for every pensioner.
While many overpayments may be small, the scale and duration make it a serious public trust issue. Pensioners should check official tax records, follow HMRC guidance and seek qualified advice where their tax position is complex.
Frequently Asked Questions
Is State Pension taxable in the UK?
Yes. State Pension is taxable if a person’s total annual income is above their Personal Allowance. It is usually paid without tax being deducted directly, so tax may be collected through other income or assessment routes.
Did the error affect only the new State Pension?
No. HMRC’s figures refer to both full basic State Pension and full new State Pension examples. The individual effect can vary by pension type, entitlement and tax year.
Is there a special overcharge form for pensioners?
There is no confirmed special form for this specific State Pension error. Pensioners should use normal official routes for P800 letters, Simple Assessment, Self Assessment amendments, refund checks or direct contact.
Could a pensioner receive an automatic refund?
Possibly, depending on the tax route and calculation. Official refund guidance says a P800 may explain how to claim online or whether a cheque will be sent automatically.
Why are some estimated overpayments so small?
The error concerns the tax effect of one week’s difference between the previous and current State Pension rate. It does not mean the whole State Pension was incorrectly taxed.
Can older tax years still be challenged?
That depends on the tax year, the tax route, legal time limits, HMRC’s correction process and individual circumstances. Pensioners should check official guidance before assuming older amounts can be reclaimed.
Should pensioners use a refund company?
Caution is advisable. Many pensioners can check official records themselves. A regulated adviser may help in complex cases, but claimants should avoid unverified firms requesting personal or banking details.
Editorial Note:
This article is a professional UK tax and pension news explainer. It is informational, not financial/legal advice. It does not state that every State Pensioner is due compensation, nor does it guarantee a refund.
The article separates confirmed information, estimates, upper-limit figures, practical checks and unrelated pension tax searches. No invented spokesperson quotes have been used.
How We Checked?
The article was checked against HMRC’s 1 July 2026 letter to the Treasury Committee, official pension tax guidance, official overpayment and refund guidance, and the user-provided reference reporting for news context. The official letter was treated as the primary source for the admission, affected tax routes, dates, estimates and quoted apology.