5.6 Million Brits Are on the Wrong Tax Code — The 5-Minute Check That Could Get You Money Back

HMRC has confirmed millions of workers are on the wrong tax code in 2026. Here's the simple check everyone should do right now, and how to claim what you're owed.

15 June 2026·5 min read

HMRC's own data suggests more than 5.6 million workers in the UK are on an incorrect tax code at any given time. That means one in six employed workers may be silently paying the wrong amount of tax every month — most of them paying too much. The good news: this check takes five minutes.

Step 1: Find Your Tax Code

Your tax code is on your payslip (usually in the top section, sometimes labelled "Tax Code" or "PAYE Ref"). It's a number followed by a letter — for example, 1257L.

Step 2: Understand What It Should Be

For the vast majority of workers in England, Wales and Northern Ireland with one job and no unusual circumstances, the correct code is 1257L. This represents the standard Personal Allowance of £12,570.

If your code is different — lower number, BR, 0T, K code, or W1/M1 — there's a reason. The question is whether that reason is valid.

Step 3: Check Your Personal Tax Account

Log in to gov.uk/personal-tax-account. Under "Pay As You Earn", you'll see your current tax code and the explanation HMRC holds for it. Common wrong reasons include:

An old company car benefit that was never removed
HMRC estimating your savings interest incorrectly
A previous year's underpayment being collected via code
No P45 from a previous employer, triggering emergency code

Step 4: Challenge If Wrong

If the reason is outdated or incorrect, you can challenge it directly in your Personal Tax Account. HMRC will issue a corrected code to your employer within days, and your next payslip will begin recovering any overpaid tax automatically.

Frequently Asked Questions

How far back can I reclaim overpaid tax?

HMRC allows you to reclaim overpaid tax going back 4 tax years. So in the 2026/27 tax year, you can claim refunds dating back to 2022/23.

How do I get the refund?

HMRC sends either a P800 notice (with an online claim link, refunded within 5 working days) or a cheque automatically. If you believe you're owed more than what's offered, you can appeal or write to HMRC directly.

Check your tax code right now with our Tax Code Checker.

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