Tax Code Correction Request Letter: Free Template and What to Include

If you need to request HMRC correct an incorrect PAYE tax code, a written letter is the recommended first step — it creates a clear record and shows you're pursuing the matter formally. Below is what a strong tax code correction request should include.

What this letter needs to cover

• State the incorrect code being used and what the correct code should be
• Explain why the code is wrong (previous employment, benefits in kind incorrectly included, etc)
• Request immediate amendment and notify the employer
• Ask for confirmation and calculation of any overpaid or underpaid tax

Why tax codes go wrong more often than you'd expect

Tax codes are frequently based on outdated or incomplete information — a previous job that hasn't been closed off properly, a benefit-in-kind no longer received, or a change in personal allowance that hasn't updated. An incorrect code can mean you're paying too much or too little tax without realising, sometimes for months before it's noticed.

What to include before you send it

• Your current tax code as shown on your payslip, and what you believe it should be
• The reason you believe it's wrong — for example, an old employment still showing, or an incorrect benefit-in-kind
• Any relevant supporting information, such as your P45 or P60 details
• A request for the correction to be made and confirmed in writing

What happens once it's corrected

HMRC will issue a new tax code notice to both you and your employer, and any overpaid or underpaid tax is generally adjusted through your pay going forward, or refunded/collected separately depending on the amount and timing. It's worth checking your next payslip carefully to confirm the correction has actually been applied.

Frequently Asked Questions

How do I check if my tax code is correct?
HMRC's online tax checker service, or your personal tax account, can confirm what your code should be based on your current circumstances.

Can I claim back tax I've overpaid due to a wrong code?
Yes — once corrected, any overpayment can generally be refunded, and HMRC can look back over previous tax years if the error has persisted for some time.

[Your Name]
[Your Address]
[Your Postcode]
[Your Telephone Number]
[Your National Insurance Number]
[Your Employer's PAYE Reference, if known]
HM Revenue and Customs
[The address on your HMRC letters or on gov.uk]
[Date]

Dear Sir / Madam,

Subject: Request to correct my tax code

I am writing to ask you to review and correct my tax code for the [e.g. 2026/27] tax year. My current code at [Employer Name] is [current code, e.g. 1257L / BR / K100]. I believe it is wrong and should be [the code you think is right, if you know it].

I believe my code is wrong because: [choose and edit]
• [Wrong deductions: My code includes [e.g. a company car I no longer have / medical insurance that ended on [Date]].]
• [More than one job: I changed jobs on [Date] and my personal allowance is still being given to my old job, so my main job is being taxed too much.]
• [An underpayment adjustment: The adjustment for an underpayment from a previous year uses the wrong figures.]

Please correct my code and tell my employer, and confirm in writing what my new code is and how much tax I have overpaid or underpaid.

I have enclosed copies of my latest [payslip / P45 / P60].

Yours sincerely,

[Your Signature]
[Your Printed Name]