UK Tax Codes · 2026/27
T Tax Code Meaning — Items Under Review (UK 2026/27)
Who gets the T tax code?
T is most often applied when (1) your code has been adjusted from the standard 1257L for specific reasons, (2) you have multiple sources of income that HMRC needs to manually balance, (3) you've recently had a status change (residency, BIK, marriage) that requires review, or (4) HMRC has flagged your case for monitoring.
How T affects your pay
T codes follow whatever number/letter combination they're attached to (e.g. 1257T uses £12,570 allowance like 1257L). The functional impact is the same as the equivalent letter code — what's different is HMRC's flagging that the code is non-standard for some reason.
When to check this code
Check T whenever you receive it, because it indicates HMRC is treating your case as needing manual oversight. Often the trigger has resolved (e.g. a temporary issue) but the code is still T. Verify your code's basis in your HMRC personal tax account.
What to do if it's wrong
T codes don't necessarily mean an error — they often mean 'manually calculated and under review.' Contact HMRC if you don't understand why your code is T and want to confirm whether it should revert to L. They'll explain the reason and confirm whether the T classification still applies.
Example calculation
On £30,000 with 1257T: same as 1257L — first £12,570 tax-free, then 20% on £17,430 = £3,486 income tax. The T flag doesn't change the calculation; it just signals manual review.
Recruiter pro tip
T codes that persist for years are usually fine — they indicate a stable but non-standard situation HMRC has reviewed. T codes that appear suddenly often signal HMRC has flagged a change in your circumstances. Either way, it's worth understanding why your code is T rather than L. The HMRC personal tax account shows the code basis in plain English.
Related tax codes
1257L
1257L is the standard UK tax code for 2026/27. It means you're entitled to the full £12,570 personal allowance…
K — Owed Tax Adjustment
K codes (e.g. K123, K500) mean you have less than zero personal allowance — typically because of underpaid tax…
M — Marriage Allowance
M at the end of your tax code (e.g. 1383M for 2026/27) means you receive 10% of your spouse or civil partner's…