Last updated: 14 October 2026
HMRC says you’re owed money: is it a tax code error or a scam?
It can be either. HMRC does tell people when they’ve overpaid tax, but genuine notices come as a P800 tax calculation letter, a message in your personal tax account, or in the HMRC app. They’re often caused by a wrong tax code, for example after a change of job. A text, email or call offering a refund with a link to click, or asking for bank details, is almost certainly a scam. Always check by logging into your account yourself.
Genuine refund or scam?
| Genuine HMRC | Likely scam |
| P800 letter after the tax year ends | Text or email with a refund link |
| Message in your personal tax account or the HMRC app | Request for card details or a PIN |
| Refund paid to an account you add securely in your HMRC account | “Claim within 24 hours” pressure |
| Explains the tax year and the calculation | No details of how the refund arose |
Why tax codes go wrong
- Starting a new job without a P45, so an emergency code applies
- Two jobs, or a job and a pension, with the allowance in the wrong place
- A company car or medical insurance added, or removed, late
- Estimated savings interest or other income that turned out lower
- Marriage Allowance not reflected
- HMRC still collecting old underpaid tax after it’s been paid
Reading your tax code
The standard code for 2026/27 is 1257L, meaning £12,570 of tax-free pay. A lower number means HMRC is collecting tax on something else, such as benefits or untaxed income. A K code means the deductions are more than your allowance. If your code looks wrong, check the breakdown in your personal tax account and update HMRC.
Example
Omar changed jobs in May 2026. His new employer used emergency code 1257L on a week 1 basis, so he wasn’t given credit for the unused allowance from his first month. By the time HMRC sends his new code in July, he has overpaid around £150. HMRC refunds this through his next pay, after updating his code. If it hadn’t, he’d receive a P800 after 5 April 2027.
How refunds are paid
For a P800 refund, you can usually claim online through your personal tax account and get the money in about 5 working days. Otherwise HMRC sends a cheque. If you’re still employed, an in-year overpayment is normally repaid through your payroll after your code is corrected.
If you’ve responded to a scam
- Contact your bank immediately.
2. Change your HMRC and email passwords.
3. Report it to HMRC and Action Fraud.
4. Watch your personal tax account for changes.
Underpayments too
Tax code errors can also mean you’ve paid too little. HMRC usually collects up to £3,000 a year through your next year’s tax code, or asks you to pay directly.
Frequently asked questions
Can I ask HMRC to review my code?
Yes, through your personal tax account or by phone.
Will I get interest on a PAYE refund?
Not usually on in-year PAYE refunds.
Can my employer change my tax code?
No, only HMRC can issue a new code.
Does HMRC send texts?
Sometimes, but never with refund links.
Related: PAYE code message scams, a new employee with no P45 and claiming overpaid tax.
Talk to Accotax
Want this handled for you? Our team at Accotax can help with checking your tax code and refunds. See our small business accountants service, or contact us for a free, no-obligation quote.
This page is general guidance based on HMRC rules for the 2026/27 tax year, checked against gov.uk on 14 October 2026. It is not personal advice, so speak to an accountant about your own situation.
