Jasmine Birtles
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How to claim back overpaid tax: a plain-English guide for UK employees
Moneymagpie Team
29th Sep 2026
A new job, an unexpectedly small payslip or a tax code you have never checked can leave you wondering whether you have paid too much tax. You might have, but a surprising deduction is not proof that HMRC owes you money. The first step is to work out why you think you overpaid. A mistake in the tax taken from your wages and tax relief on work expenses are different issues, with different ways to put them right. Check your HMRC Personal Tax Account for a tax calculation or incorrect employment details, then follow the route that fits: a P800 repayment, a tax-code correction or a job-expenses claim. Here is how to check your records, look back over earlier tax years and make a claim safely.
- Why employees can pay too much tax
- Check your tax record before assuming you are owed anything
- How far back can you claim? The four-year rule
- Doing it yourself through HMRC or using a refund service
- How to spot a tax refund scam
- What happens after you claim
Why employees can pay too much tax
Most employees pay Income Tax through PAYE, with their employer deducting it from each payslip. Your tax code tells the employer how much tax-free income to allow for. If the code is wrong, you could pay too much or too little. This can happen when you start a job before your new employer has your P45, or when HMRC needs to account for income from more than one job. An emergency code may be used until HMRC has the information it needs. Look at the whole code on your payslip: suffixes such as W1 or M1 mean tax is being calculated on that pay period rather than cumulatively across the year.
There is another possibility: you paid the right tax on your wages but missed tax relief on eligible expenses you had to meet for work. Depending on the rules, these might include maintaining a required uniform, buying tools needed for your job, qualifying business mileage or paying an approved professional subscription. Ordinary commuting does not count, and you cannot claim relief on costs your employer has fully reimbursed. Tax relief is generally a reduction in the tax you owe, not repayment of the entire purchase price.
Check your tax record before assuming you are owed anything
Gather your recent payslips, P60s for completed tax years and any P45s from jobs you left. Check the tax code on each payslip and compare your employment details with those in your HMRC Personal Tax Account. In particular, look for an old job still showing as current, missing income information or a change of employer that could explain why an emergency code appeared. HMRC’s tax code guidance explains what the letters and numbers mean, but the same code can produce different results depending on your circumstances.
For a completed tax year, check whether HMRC has sent you a P800 calculation showing that you paid too much or too little Income Tax. If it says you are due a refund, follow the instructions on the calculation rather than starting a duplicate claim. If your code looks wrong in the current year, update your employment details with HMRC; give your employer your P45 if you have one. HMRC can then check the code, while your employer uses the code it receives to calculate future deductions. Keep in mind that a large deduction on one payslip may balance out later in the year.
How far back can you claim? The four-year rule
It is worth reviewing earlier years as well as this year’s payslips. The usual window for claiming back overpaid Income Tax is the current tax year and the previous four tax years. On 28 September 2026, the current year is 2026/27, so the four previous years run from 2022/23 through 2025/26. A claim for 2022/23 generally needs to reach HMRC by 5 April 2027. After that, the oldest year falls outside the standard four-year window.
Check each year separately. A job change, a period with two employers or a work expense may affect one year but not the next. Keep the relevant P60, payslips and expense records together so you can see what you earned, what tax was deducted and which costs you actually paid. The time limit does not make every expense allowable or guarantee a repayment: the underlying tax and eligibility rules still apply.
Doing it yourself through HMRC or using a refund service
You can deal with HMRC directly without paying a refund company. For a tax-code problem, check your details in your Personal Tax Account and tell HMRC what needs correcting. If HMRC has already issued a P800 showing an overpayment, use the repayment instructions it provides. For eligible job expenses, you may be able to claim through HMRC’s online service or send form P87 by post. The postal job-expenses guidance sets out the conditions: a postal claim must be within four years of the end of the relevant tax year, the total expenses claimed must be £2,500 or less for that year, and you must have paid tax in that year. If your expenses exceed £2,500, you need to use Self Assessment instead.
A paid refund service is another option if you would rather have help preparing a claim. Taxpro is one such service; for PAYE refund claims its fee is 37.5% plus VAT, taken from the refund. The distinction matters when weighing up the options: claiming directly through HMRC avoids a service fee, while a paid service reduces the amount of any refund you keep. Before appointing any company, read its fees and authorisation terms, check what it will claim for and make sure you understand where HMRC will send the repayment.
Whichever route you choose, provide accurate information. HMRC may ask for receipts or other evidence, and using a company does not remove your responsibility if a claim made on your behalf is incorrect. Do not estimate expenses you cannot substantiate simply because a form or an advert suggests you might qualify.
How to spot a tax refund scam
A genuine possibility of a refund makes an unexpected message tempting to believe. Be wary of texts, emails or calls that announce a refund and push you to enter bank details immediately. Other warning signs include a demand for your Government Gateway password, an upfront payment to “release” money, or pressure to act before you have checked the claim. A message can display a convincing name or logo and still be fraudulent.
Instead of tapping a link in a message, type GOV.UK into your browser yourself and sign in to your HMRC account from there. If you have received a P800, use the instructions on the document and check anything that seems unusual through an official HMRC contact route. The same care applies when considering a refund company: confirm who you are authorising, what information it needs and how it will be paid. Never give anyone your Government Gateway password to manage a claim for you.
Be especially cautious of promises that you qualify for a particular amount before anyone has examined your income and expenses. A legitimate claim depends on your circumstances and evidence, not on a headline figure. Taking a few minutes to verify a message is safer than responding while you feel rushed.
What happens after you claim
HMRC may need further information before it can settle a claim, particularly where you are seeking relief for expenses. Keep copies of what you submit, including receipts, forms and correspondence, and watch for requests sent through official channels. If a tax code was the problem, HMRC may correct it so that future pay is taxed differently. Depending on the circumstances, an overpayment may be dealt with through payroll or repaid separately, for example to a bank account or by cheque. Do not assume that a code change and a repayment are the same thing; check what HMRC’s calculation says has happened.
Once a claim has been resolved, compare your next payslip with the corrected code and keep the calculation with your tax records. That makes it easier to spot a repeated problem, especially after another job change. The most useful starting point is modest: check your own record, identify the year and reason for a possible overpayment, then choose whether to handle the claim directly with HMRC or pay for assistance.
Disclaimer: MoneyMagpie is not a licensed financial advisor and therefore information found here including opinions, commentary, suggestions or strategies are for informational, entertainment or educational purposes only. This should not be considered as financial advice. Anyone thinking of investing should conduct their own due diligence.
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