Taxpayers urged to check if they have overpaid after 730,000 refunds go unclaimed

Britons have been urged to check whether they have overpaid tax.

Those who are due a PAYE repayment receive a P800 tax calculation letter, which will tell them the amount they are due to get back.

Refunds aren't always automatic, however, and around 730,000 went unclaimed last year, HMRC data shows.

The average refund was £855, meaning £624m was left unclaimed.

Taxpayers have four years from the end of the relevant tax year to claim a refund.

Adelle Greenwood, tax manager at the Institute of Chartered Accountants in England and Wales, said: "Taxpayers will need to check that their P800 calculation is accurate and contains all relevant data."

You should be checking your P800 to ensure your tax code is correct and all allowable employment expenses (eg, uniforms, tools, professional subscriptions, mileage) are included.

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The quickest way to claim money back is via the HMRC app - or you can also claim within your personal tax account on the HMRC website, with bank transfer and cheque options.

Online repayments are made in five working days, while repayment by cheque will take up to six weeks.

If you believe the P800 is wrong you must inform HMRC, even if they have repaid you too much, to avoid potential penalties.

Who might have overpaid tax?

Typically, tax is collected through the PAYE system, which means it is automatically taken from wages or pensions, but mistakes can be made.

Repayments are usually owed because of an incorrect or outdated tax code, or the taxpayer not having been allocated the full personal allowance for the year, according to the Institute of Chartered Accountants in England and Wales.

Other reasons could include the person not working for the full tax year, changing jobs or working hours during the year.

Pensioners may be due a refund if the incorrect amount of state pension has been included in their tax code.

(c) Sky News 2026: Taxpayers urged to check if they have overpaid after 730,000 refunds go unclaimed