15th June 2026
HMRC overcharged pensioners by around £5 because of a system error in how the State Pension increase was calculated — and refunds can be claimed.
Here is a clear, evidence‑based breakdown of what went wrong, who is affected, and how pensioners can get their money back, with citations.
What went wrong — the HMRC pension tax error
HMRC admitted that its automated system used the wrong number of weeks when calculating State Pension income for self‑assessment tax returns.
The technical error
HMRC should have calculated pension income as:
51 weeks at the new (higher) rate, and
1 week at the previous year’s rate
Instead, the system incorrectly used:
52 weeks at the new rate
This inflated pension income slightly and caused a small tax overcharge of around £5 for most affected pensioners.
How many people were affected?
Around 1.7 million pensioners who complete self‑assessment returns
Some reports suggest the total number of overcharged pensioners could be as high as 8.7 million, depending on how the error was counted across tax years
Why only some pensioners were affected
This issue only affects pensioners who file self‑assessment tax returns, such as those who:
Are self‑employed
Have rental income
Have complex income sources
Pensioners who only receive State Pension or workplace pensions and do not file self‑assessment were NOT affected.
How pensioners can get a refund
HMRC has confirmed that anyone who overpaid tax can claim a repayment.
Here are the steps:
1. Check your State Pension figure on your tax return
Compare the amount HMRC pre‑filled with your actual State Pension statement.
2. Correct the figure manually before submitting
If you haven’t filed yet, you can override the incorrect figure on your self‑assessment return.
3. If you already submitted, file an amendment
You can amend your return up to 12 months after the 31 January deadline.
4. Request a repayment from HMRC
HMRC says pensioners who believe they overpaid can request a repayment directly.
You can do this by:
Logging into your HMRC online account
Calling HMRC and asking for a Simple Assessment review
5. If unsure, contact HMRC for clarification
HMRC has apologised and confirmed they will help pensioners correct the error.
Why this happened
This was a system logic error in HMRC’s automated pre‑population of pension data — specifically a “52‑week logic error”.
Experts have called it “remarkably careless” and warned that pensioners should not rely solely on pre‑filled figures.
HMRC used 52 weeks at the new pension rate instead of the correct 51/1 split.
Most pensioners were overcharged around £5.
1.7 million self‑assessment pensioners were affected (possibly more across all tax years).
Pensioners can amend returns and request refunds.
HMRC has apologised and is correcting the issue.
It may have happened in earlier years but you need to compare your self assessment with your actual pension figures. HMRC will not do it automatically.