# UK HMRC state pension tax calculation error

> Live situation record from CLSTR: https://clstr.news/situations/uk-hmrc-state-pension-tax-calculation-error
> Updated: 2026-09-27T11:52:40.000Z. Sources: 7. Developments: 2.

HMRC has identified a calculation error affecting approximately 3.2 million pensioners in the UK, with total estimated repayments of roughly £19.3 million.

The error stemmed from HMRC incorrectly applying increased pension rates to all 52 weeks of the tax year, rather than accounting for the one week at the previous rate when annual increases take effect. This resulted in an overstatement of annual pension income and subsequent overcharging of taxes.

The correction exercise applies to cases from the 2020/21 tax year onwards. HMRC intends to issue repayments automatically through methods such as PAYE adjustments or Self Assessment credits, meaning most affected individuals will not need to apply for a refund.

## Timeline

### 2026-09-27: HMRC error leaves millions of pensioners owed tax refunds

HMRC error regarding state pension calculations may result in tax refunds for 3.2 million pensioners, totaling approximately £19.3 million.

2 sources. https://clstr.news/cluster/hmrc-error-leaves-millions-of-pensioners-owed-tax-refunds

### 2026-09-25: HMRC error to trigger tax refunds for millions of pensioners

HMRC is set to issue approximately £19.3 million in tax refunds to 3.2 million pensioners due to a calculation error regarding state pension income rates since the 2020/21 tax year.

5 sources. https://clstr.news/cluster/hmrc-error-to-trigger-tax-refunds-for-millions-of-pensioners

---
Cite as: UK HMRC state pension tax calculation error. CLSTR, https://clstr.news/situations/uk-hmrc-state-pension-tax-calculation-error