Quick answer: HMRC has acknowledged a State Pension calculation error. Its letter of 1 July 2026 identifies about 1.4 million PAYE pensioners who overpaid in 2024/25, plus separate potentially affected Self Assessment and Simple Assessment groups. An incorrect pension figure does not guarantee a refund. Separately, an emergency tax code on a private pension withdrawal may lead to overpaid tax. Use GOV.UK’s pension refund checker to choose the right claim route.
I know tax letters are the last thing anyone wants to read, but this is one area where a ten-minute check can mean real money back. Here are the three most common pension tax and forecast problems, and exactly how to check each one.
1. The HMRC State Pension tax error
In a letter to Parliament dated 1 July 2026, HMRC explained that its system could use 52 weeks at the uprated State Pension rate instead of one week at the previous rate and 51 at the new rate. It estimated around 1.4 million PAYE pensioners overpaid in 2024/25. Separate upper estimates cover 955,000 Self Assessment and around 760,000 Simple Assessment cases; not all necessarily paid too much. Small discrepancies may fall within HMRC’s administrative tolerances.
- What HMRC is doing: investigating the historical issue and correcting the calculation. Check the latest HMRC position before assuming a refund or timescale.
- What you can do now: there’s no simple online checker yet. Compare your latest tax calculation (P800 or Simple Assessment letter) with your actual State Pension. Use DWP letters to calculate the pension due for the relevant tax year, including the annual rate change; the latest weekly amount multiplied by 52 may be misleading.
- If the figure HMRC used is higher than what you actually get, contact HMRC with your DWP letter as evidence.
2. Emergency tax on pension withdrawals
This catches thousands of people every year. When you take money from a private or workplace pension for the first time (beyond the tax-free part), your provider often doesn’t have your correct tax code. So it uses an emergency code that treats your one-off withdrawal as if you’ll get it every month, and takes far too much tax.
Emergency tax on a pension withdrawal is a separate issue from the State Pension calculation error. Use the GOV.UK pension tax refund checker before choosing a form; the correct route depends on whether you emptied the pot, stopped work and have other income. The table is a starting point, not a substitute for that checker:
| Your situation | Form |
|---|---|
| Took part of your pot, not taking regular payments | P55 |
| Emptied your whole pot and have other taxable income | P53Z |
| Stopped work, emptied your pot and meet HMRC’s P50Z conditions | P50Z |
If you take regular income from your pension, HMRC should correct your tax code over the year, so you may not need to do anything. But if you made a one-off withdrawal, don’t wait. Claim it back.
3. Incorrect State Pension forecasts
Your forecast depends on your National Insurance record, and errors are more likely if you:
- worked before April 2016 and were “contracted out” of the additional State Pension (common in public sector and big company pension schemes)
- were self-employed, lived or worked abroad, or have gaps
- claimed Child Benefit for a child under 12 (this gives you NI credits, but only if the claim was in your name)
- Check your forecast at GOV.UK: Check your State Pension.
- Click through to your National Insurance record and look for years marked “not full”.
- If a year looks wrong, for example you were working or claiming Child Benefit, gather evidence (payslips, P60s, Child Benefit letters) and contact the Future Pension Centre.
- Before paying for any missing years, read my guide to filling National Insurance gaps. Some years won’t increase your pension.
Pre-2016 pensioners: are you missing extra State Pension?
If you reached State Pension age before 6 April 2016, you’re on the old basic State Pension, and some people are entitled to more than they get. For example:
- Married women and widows may be able to get a pension based on their husband’s or late husband’s NI record. The DWP has been correcting qualifying underpayments; entitlement depends on the old pension rules and individual circumstances.
- Over-80s: if you’re 80 or over and get little or no basic State Pension, you may qualify for the “over 80 pension”. Check the over 80 pension conditions and claim guidance; it is not available to people who reached State Pension age on or after 6 April 2016.
Call the Pension Service if any of these might apply to you or a parent. The numbers are on GOV.UK.
Watch out for refund scams
Every time a “tax error” story is in the news, scam texts and emails follow. HMRC will never text or email you about a refund with a link asking for bank details. Only claim through GOV.UK or the HMRC app, and never pay a company to claim a tax refund you can claim free yourself.
FAQs
Will HMRC contact me if I’m owed money from the State Pension error?
Do not assume every incorrect calculation means a refund. HMRC’s letter describes small discrepancies and administrative tolerances. Compare your calculation with the pension due for that tax year, and contact HMRC through GOV.UK if it looks wrong.
How far back can I claim overpaid tax?
Generally up to four years. So in the 2026/27 tax year you can usually go back to 2022/23.
Is State Pension taxed at source?
No, it’s paid without tax taken off. But it counts as income, so HMRC collects any tax through your tax code on another pension or job, or by Simple Assessment. See my State Pension 2027 guide for how the £13,000 rise affects tax.
What to do next
Ten minutes this week: check your State Pension forecast, look at your last tax letter, and if you took a pension lump sum this year, check whether you were emergency taxed. If you’ve got older parents, it’s worth doing it with them too.
Last checked: 21 October 2026. This is general information, not tax advice.
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About the author: Dr Kalpana Govindaraasan is the PhD scientist, former secondary science teacher and mum behind MoneySavvyUK, turning complex household money topics into practical steps.