How to Check If HMRC Owes You a Tax Refund — and How to Claim It

Millions of UK workers are owed money by HMRC every year without realising it. Overpayments happen for a range of reasons: changing jobs, working multiple part-time roles, emergency tax codes on new employment, or receiving a one-off payment that pushed you temporarily into a higher tax bracket. HMRC collected £246bn in income tax in 2024–25, and a significant portion of that was overpaid.

Claiming a refund is straightforward — but you have to initiate it. HMRC doesn't proactively repay money you've overpaid unless you're in Self Assessment.

Why You Might Be Owed a Refund

The most common reasons for income tax overpayment include:

• Emergency tax code: When you start a new job without providing a P45, HMRC applies an emergency code (often 1257L W1 or M1), which taxes you on a weekly basis rather than accounting for your full annual allowance. This often leads to overpayment in the early months of employment.
• Multiple jobs: If you have two or more jobs, both employers may apply the personal allowance separately, or neither may apply it fully, leading to under- or over-deduction.
• Leaving work mid-year: If you stopped working before April 5 and didn't earn your full personal allowance (£12,570 in 2026/27), you may have overpaid tax earlier in the year.
• Pension lump sum: Taking a pension flexibly can trigger emergency tax, resulting in significant overpayment on a one-off withdrawal.
• Marriage Allowance: If your partner earns below the personal allowance and you're a basic-rate taxpayer, you may be entitled to a Marriage Allowance transfer worth up to £252 per year.

Step 1: Check Your Tax Code

Your tax code determines how much income tax your employer deducts. You can find it on your payslip, P60, or P45. The standard code for 2026/27 is 1257L, representing the £12,570 personal allowance. If your code is different — particularly if it has a "W1", "M1", or "X" suffix — you may be on an emergency code.

Check and correct your tax code via HMRC's online service or the HMRC app.

Step 2: Check How Much Tax You've Paid

Log in to your Personal Tax Account at gov.uk. This shows your income and tax paid for the current and previous years. Compare your total tax paid against what you should have paid on your income.

A quick sense check: the personal allowance is £12,570, above which the basic rate is 20% on income up to £50,270, and 40% above that (in England and Wales — Scottish rates differ).

Step 3: Claim Your Refund

If you're employed (PAYE): HMRC usually adjusts PAYE overpayments automatically at the end of the tax year through a P800 tax calculation, sent between June and October. If you've received a P800 saying you're owed a refund, you can claim online via gov.uk/claim-tax-refund or wait for a cheque.

If you haven't received a P800 but believe you've overpaid, contact HMRC directly or use your Personal Tax Account.

For pension lump sums: Use one of the following forms:

• P50Z — if you've left work and taken your entire pension pot
• P55 — if you've taken part of your pension flexibly
• P53Z — if you've taken your entire pension and are still working

For Marriage Allowance: Apply at gov.uk/apply-marriage-allowance. You can backdate claims up to four years.

If you're in Self Assessment: Any refund will appear in your tax return. HMRC will issue repayment after you file, typically within a few weeks if done online.

Step 4: Watch Out for Tax Refund Scams

HMRC will never contact you by text or email asking for bank details to process a refund. These messages are fraudulent. If you receive one, report it to [email protected] and do not click any links. All legitimate HMRC refunds are processed through your Personal Tax Account or by post.

In the US, the IRS processes tax refunds via the 'Where's My Refund?' portal and operates similarly — refunds must be claimed if overpaid. In Australia, the ATO automatically processes tax refunds for most PAYG workers who lodge their annual return.

Checklist

• Check your tax code on your payslip — it should be 1257L for most people
• Log in to your Personal Tax Account at gov.uk
• Check income and tax paid for the current and previous tax year
• Review whether you started a job without a P45 (emergency tax likely)
• Check if a P800 tax calculation has been sent by HMRC
• Claim online, by phone, or via the relevant form
• Consider backdating Marriage Allowance claims up to 4 years
• Never share bank details in response to an email or text claiming to be HMRC

Key Numbers

• Personal allowance 2026/27: £12,570
• Marriage Allowance: up to £252/year
• You can backdate refund claims 4 tax years

Sources

• GOV.UK – Claim a Tax Refund
• GOV.UK – Personal Tax Account
• GOV.UK – Income Tax Rates and Allowances
• GOV.UK – Identify HMRC Scam Contacts

Educational content only — not financial advice.