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How do I get a UK tax refund or fix the wrong tax code?

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UKPublished 6 October 2026 · Written by BuyMeWhiskey Editorial Team · How we check facts

Start with HMRC, rather than a paid tax-rebate company. Check your tax code and Tax Account first, then use HMRC's refund process if you have actually overpaid. For 2026/27 the standard Personal Allowance is £12,570.

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Check your tax code and refund position through HMRC’s official tax-refund service or Personal Tax Account.

Check HMRC tax refund guidance

Run your own numbers: UK take-home pay calculator 2026/27.

A wrong tax code can cause an overpayment

PAYE normally adjusts tax during the year using the tax code HMRC gives your employer or pension provider. For 2026/27 the standard Personal Allowance is £12,570, and HMRC says the emergency code used for many employees is 1257L.

If HMRC has incomplete or outdated information—such as an old job, incorrect benefits or another source of income—the code can be wrong. That can lead to too much or too little tax being deducted from pay.

What 0T means

HMRC says tax code 0T means there is no tax-free allowance available for that job or pension. It can be used when your Personal Allowance has been used up or when you start a new job and the employer does not yet have enough information to give you the right code.

0T does not automatically mean you owe extra tax overall. It means PAYE is currently calculating tax on that income without a Personal Allowance. The wider tax-year calculation decides whether you ultimately overpay or underpay.

Check the code before asking for a refund

HMRC's tax-code checker lets you see what the letters and numbers mean and update information that is wrong. The checker asks for information such as your tax code, annual income, company benefits and State Pension where relevant.

If the information is wrong, fixing the record can change your future PAYE deductions. It can also prevent the same error repeating across the next tax year.

A P800 is a year-end reconciliation

If you are employed or receive a pension and HMRC calculates that you have paid too much or too little Income Tax after the tax year, you may receive a P800. GOV.UK says these letters are sent between June and March of the following tax year.

If the P800 says you are due a refund, HMRC's current guidance says you may be able to claim online, through your Personal Tax Account or the HMRC app. An online claim can normally be paid within 5 working days; a cheque request can take longer.

You do not need a rebate company for the basic process

HMRC provides the refund route itself. Be cautious about unexpected texts, emails or callers asking for your bank details or charging a large percentage simply to submit a refund claim. Use GOV.UK directly rather than a link in an unsolicited message.

A professional adviser or accountant may be useful for complicated tax matters, but a standard PAYE refund can often be checked and claimed directly.

What about older tax years?

Some refund claims cover earlier tax years, and HMRC has different methods depending on why the tax was overpaid. GOV.UK's tax-refund service helps route you to the correct process for employment income, expenses, Self Assessment and other situations.

Do not assume that because you changed jobs, retired or started receiving a pension you are automatically due a refund. Check the actual tax deducted against the tax that should have been due.

Why a tax code can change mid-year

Tax codes can change when HMRC receives new information about your income, benefits, pensions or other taxable amounts. On a cumulative code, payroll considers previous pay and tax during the year, which can sometimes correct an earlier over- or under-deduction as the year progresses.

That is why a sudden change in take-home pay does not, by itself, prove HMRC has made a mistake. Check the coding notice and the information behind it first.

When to contact HMRC

Contact HMRC when the facts on the tax-code checker are wrong, when you believe a P800 calculation is incorrect, or when a refund claim does not reflect the tax actually deducted. Keep your P45, P60, payslips and pension statements so you can explain the difference.

Illustrative Personal Allowance difference

Worked example

Illustrative PAYE example: suppose an employee should have had £12,570 of tax-free Personal Allowance for 2026/27 but payroll temporarily operated a code that gave them £10,000 of tax-free income. The simplified difference is £12,570 − £10,000 = £2,570.

At an illustrative 20% rate, the tax on that difference would be £2,570 × 0.20 = £514. That is not a real refund calculation because PAYE bands, previous pay, National Insurance and the reason for the code all matter. It simply shows why the tax-free allowance embedded in a code can affect deductions.

In practice, the tax code may also reflect taxable benefits, previous pay, pension income or other adjustments, so the final refund cannot be inferred from the allowance difference alone.

How do I claim a UK tax refund in 2026?#

Start with HMRC’s official tax-refund service or your Personal Tax Account. HMRC can tell you which refund route applies based on the reason for the overpayment. Do not pay a third party simply to submit a standard claim that HMRC lets you handle directly.

What does tax code 1257L mean in 2026/27?#

It is the code HMRC says is currently used for most people with one job or pension and represents the standard £12,570 Personal Allowance. Your actual code can differ if HMRC needs to account for other income, benefits or deductions. The code does not itself mean that you will receive £12,570 in cash; it indicates the allowance being applied through PAYE.

What does 0T mean on a payslip?#

HMRC says 0T means there is no tax-free allowance available for that job or pension. It can be used when your allowance has been used up or when a new employer lacks enough information to allocate the correct code. If a new employer has incomplete information, the code can be temporary until HMRC receives the correct details.

How long does an HMRC tax refund take?#

For a P800 that says you can claim online, HMRC currently says an online bank-transfer refund is normally sent within 5 working days. A cheque request can take longer. The exact timing depends on the route HMRC tells you to use.

Can I claim an old PAYE overpayment?#

Possibly, but the correct process depends on the tax year and reason for the overpayment. GOV.UK has different routes for employment income, Self Assessment, expenses and other circumstances. Gather your P60s, payslips and other records before claiming. The tax year and reason for the overpayment can change the route HMRC expects you to use.

Do I need a tax rebate company?#

Usually not for a straightforward PAYE refund. HMRC provides its own online services and Personal Tax Account routes. A regulated professional may be useful for complicated tax affairs, but an unexpected company asking for a large cut of a simple refund deserves caution.

Why did my tax code suddenly change?#

HMRC can change your code when it receives new information about income, pensions, benefits or deductions. Check the coding notice and HMRC’s tax-code checker before assuming the change is wrong. A cumulative PAYE code can also correct earlier deductions during the tax year. Keeping the coding notice alongside your payslips makes it easier to identify what changed.

What documents do I need to check a tax refund?#

Useful records include your P60, P45, payslips, pension statements, company-benefit details and HMRC coding notices. If HMRC’s calculation is wrong, these records help you identify which income or tax deduction differs from the figure HMRC used. Keep records for the tax year in case HMRC asks you to explain the source of an overpayment. They also help if HMRC asks you to support a refund claim with evidence.

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Next question →How can I check how much of my ISA allowance I have used?

Sources

Figures were checked against these sources before publication. If a rule changes, we update the page and show the new date.

General information, not personal financial advice. Rules depend on your circumstances; check the official source or speak to a regulated adviser before acting.