Do HMRC Automatically Refund Overpaid Tax? What To Know In 2026

HMRC sometimes refunds overpaid tax automatically, but you should not assume a payment will arrive without action. The process depends on how you paid the tax and what HMRC tells you. In particular, a P800 showing that you are owed money may still require you to claim it.

For employees, pensioners and self-employed Londoners, the practical question is whether an overpayment has simply been calculated or a repayment has actually been arranged.

Why Taxpayers Should Check Their Position This September?

September falls within HMRC’s annual window for sending tax calculation letters. These are issued between June and March of the following tax year. For the year ending 5 April 2026, that means June 2026 to March 2027.

The timetable explains why one person may hear from HMRC months before another. There is no single nationwide tax refund payday.

Employees and pension recipients may receive a P800 after an end-of-year review. People registered for Self Assessment generally have their position dealt with through their tax account instead.

This article concerns personal Income Tax. VAT, Corporation Tax and National Insurance repayments have separate rules.

What A P800 Letter Means For Your Refund?

A P800 explains HMRC’s calculation, but its payment instructions determine your next step.

What Your Letter Says	What To Do	Published Timescale
You can claim online	Request the refund through the official service	Within five working days for an online payment claim
You can claim, but want a cheque	Ask HMRC to issue one	Within six weeks
HMRC will send a cheque	No claim is needed	Within 14 days of the letter’s date

The online P800 service requires your letter’s reference number and National Insurance number. Other routes include your personal tax account, the HMRC app or contacting HMRC.

Check the figures against your records. If the calculation is wrong, tell HMRC which amounts need correcting.

Why You Might Have Paid Too Much Income Tax?

An overpayment can arise when information used to calculate deductions does not match your circumstances.

HMRC lists examples including an incorrect tax code, receiving payments from an old and new employer in the same month, and starting to receive a workplace pension.

These are reasons to review your records, rather than proof that a refund is due.

Changing jobs does not automatically mean you have overpaid, and an unexpectedly large deduction needs to be checked against your wider tax position.

Check Your Tax Code And Employment Details

Your employer or pension provider uses your tax code to calculate Income Tax deductions. You receive a code for each employment or pension.

Compare the code on your payslip with the information in your HMRC account. Check whether the jobs and pensions shown are current, and whether your records reflect a recent change.

Keep your P45 when leaving a job and give it to your new employer.

If you do not have one, complete the starter checklist accurately. HMRC’s tax code guidance explains where to find your code and the information employers need.

Do HMRC Automatically Refund Overpaid Tax After Changing Jobs?

A refund may be dealt with through your new employer’s payroll, depending on your circumstances.

HMRC says that someone who has stopped work but expects to start another job within four weeks does not need to use form P50: their new employer will make any repayment due through their salary.

That makes your next payslip an important document to check. Ask payroll to explain an adjustment you do not recognise, and keep the earlier payslip for comparison.

What If You Have Stopped Working Completely?

You may be able to claim during the current tax year using P50. Relevant situations include being unemployed for at least four weeks without claiming taxable state benefits, or returning to full-time study.

Eligibility matters. Receiving an occupational pension or taxable benefits can change the route. Someone still registered with an employment agency should check the specific instructions before applying.

The P50 guidance for people who have stopped working sets out these conditions.

How Self Assessment Tax Refunds Work?

Self Assessment taxpayers should check their return and account balance rather than wait for a P800.

A credit needs to be considered alongside any other tax becoming due. HMRC says it may use the money against tax payable within the next 45 days, such as a payment on account, instead of issuing a refund.

For example, a freelancer might see a credit after their final liability is calculated. If another payment is approaching, the practical outcome could be a lower bill rather than money arriving in their bank account.

If the repayment status is “pending”, HMRC says the refund has been created but still requires approval and payment. It does not mean the money has already been transferred. These points are covered in the Self Assessment repayment guidance.

What If Your Tax Return Contains A Mistake?

You can normally amend a return within 12 months of the Self Assessment deadline. For 2024/25, the usual amendment deadline is 31 January 2027.

After the amendment window, you may need to write to HMRC to claim overpayment relief. This has its own requirements, including identifying the year, explaining the error, stating the amount and providing a signed declaration.

Which Tax Reliefs May Need A Separate Claim?

Waiting for an annual calculation can leave another issue unresolved: HMRC may need you to report an eligible expense or claim additional relief.

Eligible Employment Expenses

You may qualify for relief on certain necessary costs paid personally for your job, including eligible professional subscriptions, work clothing or business travel.

You cannot claim for an expense your employer has fully reimbursed. If you complete Self Assessment, employment expense claims must go through your return.

Tax relief is also different from reimbursement.

As an illustrative calculation, £100 of qualifying expenses attracting relief at 20% would reduce tax by £20, subject to eligibility and sufficient tax having been paid. It would not produce a £100 refund.

The employment expense rules explain this distinction.

Additional Pension Tax Relief

Some pension contributions receive relief automatically, but additional relief may require a claim.

For example, a higher-rate taxpayer in England paying into a relief-at-source pension may need to claim beyond the basic 20% relief added by the provider.

The outcome depends on the scheme and the income taxed at the higher rate.

Check how your pension contributions are treated before making a claim, so you do not claim relief already received. HMRC explains the different arrangements in its pension tax relief guidance.

How Far Back Can You Claim Overpaid Tax?

For overpayment relief, HMRC sets a deadline of four years after the end of the relevant tax year. An overpayment relief claim for 2022/23 therefore normally needs to be made by 5 April 2027.

The clock runs from the tax year concerned, not the date you discover the mistake. Keep evidence supporting the amount claimed and check the applicable route promptly.

The four-year limit is separate from the shorter period for amending a return. HMRC’s rules for correcting returns and claiming overpayment relief explain both.

What To Do If Your HMRC Refund Has Not Arrived?

First, establish what has actually happened. A calculation, a submitted claim and an issued payment are different stages.

Before following up, gather:

• The relevant tax year
• The date you submitted the claim
• Any reference or confirmation received
• The payment method requested
• The latest message or status in your HMRC account

Use HMRC’s reply-time checker to check the current estimate for your type of request. HMRC updates the tool weekly, so it is more useful than treating an old processing estimate as a promise.

When contacting HMRC, ask whether further information is required and what stage the claim has reached. Avoid assuming that the timescale for one refund route applies to every other claim.

How To Avoid HMRC Tax Refund Scams?

An unexpected refund message should be checked independently before you provide information.

Open the HMRC app yourself or navigate to GOV.UK, rather than using a link in an unsolicited message. A convincing logo or a precise refund amount does not establish authenticity.

HMRC says it never sends tax rebate notifications or requests for personal or payment information by text. It also does not offer rebates through social media.

Suspicious HMRC emails can be forwarded to phishing@hmrc.gov.uk, while suspicious texts can be forwarded to 60599. HMRC provides further instructions for reporting suspicious communications.

What Taxpayers Should Do Now?

Check your records, identify the correct refund route and follow the instructions attached to your calculation or claim.

If you suspect an overpayment but have received no letter, HMRC’s tax refund checker can help identify the appropriate process. The checker directs you to the right route rather than submitting the claim itself.

For households budgeting around a possible repayment, wait for confirmation of the amount and payment stage before treating it as available money.