How to Get Overpaid Tax Back From HMRC

November 6, 2026 - 5 min read

Overpaying income tax is common, and it is rarely a sign of anything wrong with your return. It usually comes from how tax is collected during the year, which is an estimate that gets reconciled afterwards.

How you usually find out

HMRC compares what you paid with what you owed after the tax year ends on 5 April. If you paid too much or too little, it sends a tax calculation letter, called a P800 or a Simple Assessment, between June and March of the following tax year. The letter tells you how to get a refund or pay what you owe.

If you file a Self Assessment return you do not get these letters. Your bill is adjusted automatically when you have underpaid or overpaid, so your return is where an overpayment is dealt with.

The usual cause: the tax code

Your employer or pension provider uses your tax code to decide how much Income Tax to take, and HMRC tells them which code to use. You get a separate code for each employment or pension, so having more than one income is a common way to end up paying the wrong amount.

You can check your code online in your HMRC account, in the HMRC app, on your payslip, or on a Tax Code Notice letter. If you think it is wrong, ask HMRC to update it: that stops the overpayment building up rather than only recovering it afterwards.

Check your tax code whenever your income changes: a new job, a second job, or a pension starting.

If there is no letter but you think you overpaid

You can claim directly. GOV.UK has a short tool that asks about your situation and points you to the right route. It covers pay from a job, job expenses such as working from home or tools, redundancy payments, UK income while living abroad, savings interest, foreign income and UK income earned before leaving the UK. Pension tax refunds have their own route.

The tool does not make the claim for you. It sends you to the correct HMRC service.

Sole traders and freelancers

If your overpayment arises from your self-employed income, for example because payments on account turned out higher than your final bill, it is dealt with through Self Assessment rather than a P800.

Accurate records help here. They are the evidence for what you earned and what you could claim, and they are what lets you reduce a payment on account with confidence instead of guessing.

Time limits

Claims for earlier years can have time limits that depend on the type of claim. Check the current rule on GOV.UK for your situation rather than assuming an old year is still open.