What does the tax code
1257T mean?
1257T is the unusual case of a T code that costs nothing. You get the full allowance. What the T tells you is that HMRC is not treating your position as settled.
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Get the detailed breakdown + free reclaim guideAlmost every tax code question is really a question about money. 1257T is the exception. The number is the full standard allowance, £12,570, and someone on 1257T pays exactly the same income tax as someone on 1257L with the same salary. Not approximately. Identically.
What differs is what the code says about the state of your record, and that is worth understanding, because a T code is usually a signal that the number is about to change.
- 1257T Tax Code
- A tax code giving the full £12,570 Personal Allowance for 2026/27 with a T suffix rather than the usual L. The T means your code contains items HMRC needs to review, or that you have asked for the breakdown of your allowances to be kept off your employer's records. The tax you pay is the same as on 1257L.
What the T suffix means
The T suffix is used in two distinct situations, and the difference matters.
Your code is under review. Something about your entitlement is not settled. HMRC uses T to mark a code that should not be rolled forward automatically each April in the way an L code is, because an assumption behind it needs checking first.
You asked for privacy. A code's composition can reveal personal circumstances to whoever runs your employer's payroll. A taxpayer can ask HMRC to keep that detail out of the code, and HMRC uses a T suffix to do it. If this is you, the code is deliberate and there is nothing to investigate.
Neither meaning is adverse. Neither implies an error, a penalty, or an investigation in the ordinary sense of the word. Both simply mean that the ordinary automatic handling has been switched off for your record, and a human decision sits behind the figure instead of a rule.
Why 1257T and not 500T
The number and the letter answer different questions. The letter tells you the status of the code; the number tells you the amount.
| Code | Tax-free pay | Status | Extra tax vs 1257L |
|---|---|---|---|
| 1257L | £12,570 | Settled, ordinary | none |
| 1257T | £12,570 | Under review or private | none |
| 500T | £5,000 | Under review, restricted | about £1,514 |
| 0T | £0 | No allowance given | about £2,514 |
1257T is therefore the mildest T code there is. Our 500T page covers the same suffix on a heavily restricted allowance, where the same review flag sits alongside a £1,514 annual cost, and our T tax code page covers the suffix generally.
Worked example: 1257T on a £52,000 salary
- Gross salary: £52,000
- Subtract the allowance: £52,000 minus £12,570 = £39,430 of taxable income
- The first £37,700 is taxed at 20%: £7,540
- The remaining £1,730 is taxed at 40%: £692
- Income tax for the year: £8,232
Someone on 1257L with the same salary pays £8,232 too. There is no difference to find. Income tax only, National Insurance excluded, and an estimate to confirm with HMRC.
The most common reason: income approaching £100,000
If you earn near six figures, this is very likely why your code carries a T.
Above £100,000 the Personal Allowance is withdrawn at £1 for every £2 of income, reaching zero at £125,140. That withdrawal depends on your total income for the year, which HMRC cannot know in advance when your pay varies with bonus, commission or other sources.
So HMRC flags the code. It gives you the full allowance for now, marks it as unsettled, and expects to revisit it once the year's actual income is known. The number will not stay at 1257 if your income does cross £100,000.
The effective marginal rate through that band is the reason to care. Losing 50p of allowance for every extra pound, while that pound is also taxed at 40%, produces an effective rate of about 60% on income between £100,000 and £125,140. Anyone in that range has a strong reason to know their code is provisional rather than discovering it afterwards.
The other reasons a code gets a T
Your allowance is split between sources. Two employments, or a job and a pension, with the allowance divided between them.
Estimated income from another source. Where a figure is a projection rather than a known amount.
Complex or changing circumstances. Cases HMRC does not want updated automatically because the automatic answer would be wrong.
You asked for it. The privacy case described above.
What happens when the review closes
A T code is a temporary state in principle, so it is fair to ask what ends it. Three things can.
HMRC gets the missing information and issues a new code. If the answer confirms your entitlement, the code becomes 1257L and nothing else changes. If it does not, the number falls and you may find yourself on a restricted code instead.
The tax year ends and the position is reconciled. HMRC compares what you actually earned against what was deducted. If too little was taken, you may receive a P800 calculation showing an underpayment, which is often collected through a future code rather than billed. If too much was taken, a refund follows.
Nothing happens at all. This is the outcome to guard against. A T code carries forward when nobody supplies the missing fact, so a review opened three years ago can still be open, still provisional, and still nobody's task. There is no internal timetable that forces it to close.
The reason to care about the middle case is that a full allowance now can mean an underpayment later. If your income does cross £100,000 and your code gave you the whole £12,570 all year, the allowance you were not entitled to has to be recovered. That recovery lands as a deduction in a future code, which is how a costless code today becomes an expensive one in two years' time.
None of that is a reason for alarm. It is a reason to make sure HMRC's estimate of your income is right while the year is still running, because that is the one point at which correcting it is easy.
What to do about it
Nothing urgent, and that is the honest answer. You are on the full allowance and paying the correct tax for it today.
Find out what is under review. Sign in to your Personal Tax Account at gov.uk/personal-tax-account, open "Check your Income Tax" and look at the breakdown. If the composition explains itself, you are done.
Correct any estimate that is wrong. This is the step that prevents an unpleasant surprise. If HMRC is projecting income you will not receive, or missing income you will, the correction is far easier now than after a reconciliation.
Expect the code to change if your income is near £100,000. Plan for it rather than being caught by it.
If the breakdown does not explain the T, call 0300 200 3300 and ask specifically what is under review and what HMRC needs to close it. T codes frequently persist because nobody supplied a missing fact. Our guide to checking your tax code covers where each figure appears, and the wrong tax code page covers what to do when HMRC's record disagrees with yours.
Our free tax code checker will estimate the right code for your circumstances, including the effect of the taper if your income is in that range. It gives an estimate, not advice.
People also ask
- 1257T gives the full £12,570 Personal Allowance, exactly like 1257L
- The tax you pay is identical, so the code costs you nothing today
- The T suffix marks a code as under review, or as deliberately kept private from your employer
- The number tells you the amount and the letter tells you the status, which is why 1257T and 500T are so different
- Income approaching £100,000 is the most common reason, because the allowance taper depends on your final income
- Between £100,000 and £125,140 the effective marginal rate is around 60%
- The useful action is to correct any estimate now, before a reconciliation does it for you
Related tax codes: T tax code | 500T tax code | 1257L tax code | 0T tax code | Wrong tax code?
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