HMRC Tax Refunds and P800 Letters: How to Check and Claim

Common reasons you are owed a tax refund

• You were on an emergency tax code (1257L W1/M1 or 0T) after starting a job.
• You changed jobs and were paid by both employers in the same month.
• You stopped working part-way through the year.
• You took a first flexible withdrawal from a pension, which is often taxed as if you will receive it every month.
• You paid for work expenses such as uniforms, tools or professional fees that your employer did not reimburse.
• HMRC had the wrong information, for example about company benefits.

P800 letters: what they are and when you get them

A P800 compares the tax HMRC records show you should have paid with the tax actually deducted through PAYE. It is sent to employees and pensioners who are not in Self Assessment. If you file a Self Assessment return, any over- or underpayment is dealt with in that return instead.

If your P800 says you can claim online, use the GOV.UK service with the P800 reference and your National Insurance number, your personal tax account or the HMRC app. If it says you will get a cheque, you do not need to do anything.

How to check if you are owed a tax rebate

Sign in to your HMRC personal tax account or app and use "Check how much Income Tax you paid last year". It shows whether you paid the right amount for the previous tax year once HMRC has reconciled it. For the current year, compare your tax code and year-to-date figures on your latest payslip with what you expect to earn by 5 April.

Example: you start a £36,000 job in October 2026 having not worked since April, and you are put on 1257L M1. Each month only one-twelfth of the allowance is used, so by April you have used half of your £12,570 allowance. The unused £6,285 at 20% is £1,257 of overpaid tax, which HMRC should return via your payslip once the right code is applied, or by P800 after the year ends.

Refund forms: P50, P55, P50Z and P53Z

HMRC aims to repay pension overpayment claims within 30 days. If you do nothing, any overpayment is usually corrected after the tax year ends.

Time limits

You can claim a refund for up to four years after the end of the tax year. Claims for 2022/23 must reach HMRC by 5 April 2027.

Beware of tax refund scams

HMRC never tells you about a refund by email, text or voicemail asking for bank or card details, and never asks you to click a link to claim. Real P800s arrive by post or in your personal tax account. Forward suspicious emails to phishing@hmrc.gov.uk and texts to 60599.

Be cautious with refund agents. Some charge 30% or more of what HMRC would refund you for free, and you may unknowingly assign your refund to them. You can claim everything yourself through GOV.UK.

Work expenses you can claim back

If your employer does not reimburse you, you can claim tax relief on: cleaning or replacing a specialist uniform (flat-rate amounts by industry, commonly £60 a year); professional subscriptions on HMRC's approved list; business mileage in your own vehicle at 55p a mile for the first 10,000 miles from 6 April 2026 (45p before then) and 25p after that, minus anything your employer pays; and working-from-home costs of £6 a week, but only if your employer requires you to work from home. Relief is given at your tax rate, so a £60 uniform allowance saves a basic-rate taxpayer £12 a year. Claims can be backdated four years.

If the letter says you owe tax

If a P800 shows an underpayment, HMRC usually collects it through your tax code in equal instalments over the 12 months from the next 6 April, with no lump sum to pay.

This happens automatically if you are paid through PAYE, earn enough above your personal allowance to cover it, and owe less than £3,000. If it cannot be collected this way, HMRC writes with other options, often a Simple Assessment letter. For 2025/26 underpayments, a Simple Assessment issued before 31 October 2026 must be paid by 31 January 2027. If it is issued later, you have 3 months from the date of the letter.

You can pay early if you prefer a normal tax code next year. If you think the figures are wrong, for example a benefit you no longer receive, contact HMRC before the coding change takes effect.

Checking a P800 line by line

• Income from each job and pension: compare with your P60s and the P45 from any job you left.
• Benefits in kind: check the company car or medical insurance values match your P11D.
• Allowances and reliefs: check Marriage Allowance, job expenses and Gift Aid are included if you claimed them.
• Taxable state benefits: Jobseeker's Allowance, contributory ESA and the State Pension are included even though they are paid without tax deducted.
• Tax paid: compare with the total tax shown on your P60s and final payslips.