Is a T code worse than an L code?

No - PAYE calculates tax on a T code exactly as on an L code with the same number. The difference is that HMRC reviews T codes itself instead of telling employers to apply a Budget change to them automatically (PAYE Manual PAYE11075). The numeric portion is your tax-free amount divided by 10.

Why has my code changed from L to T?

One reason is that your expected income has gone above £100,000, so HMRC has tapered your Personal Allowance. Other triggers in HMRC's PAYE Manual (PAYE11045) include car or van fuel benefit, a request from you, and some second-job codes. Marriage Allowance is not one of them - it gives M or N. Your Personal Tax Account shows the "how we calculated your tax code" breakdown.

Does T mean I will owe tax at year-end?

Not necessarily. T just indicates special items in the calculation, not a likely underpayment. The numeric portion is HMRC's best estimate of your tax-free amount for the year - if it accurately reflects your circumstances, no year-end adjustment is needed. With a taper T code, the estimate of your income is the thing to check.

Can I switch from T back to L?

Yes, when the item that triggered T goes away - for example your income falls back below £100,000 so the taper no longer applies, or fuel benefit ends. HMRC then issues a new code, normally with the L suffix. If the T is only there because you asked for it, ask HMRC to remove the permanent suffix.

Tax Code · 2026/27

T Tax Code Suffix: Special Items in Your Tax Calculation

A T suffix means your tax code "includes other calculations to work out your Personal Allowance" (gov.uk). HMRC reviews T codes itself rather than letting employers apply a Budget change automatically. The number still represents your annual tax-free amount.

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What the T suffix tax code means

T after the numbers (e.g. 757T or 1257T) means the code includes items outside the standard allowance-plus-adjustments pattern. gov.uk describes it as "your tax code includes other calculations to work out your Personal Allowance".

The practical difference from L is administrative. HMRC's PAYE Manual (PAYE11075) explains that suffix L lets HMRC tell employers to raise every L code by a standard amount when the allowance changes in a Budget. T is used where HMRC does not want that to happen automatically: those are codes it reviews before telling the employer to change anything.

The numeric portion behaves identically to an L code - it is your annual tax-free amount (numeric × 10 = £ tax-free, so 757T = £7,570).

One trigger is the Personal Allowance taper. PAYE11045 applies T to any code where the allowance has been tapered below the standard amount, including to zero, unless the result is a K code. Above £100,000, £1 of allowance goes for every £2 of income. Marriage Allowance is NOT a T case: the recipient gets M and the transferor N. Nor is the High Income Child Benefit Charge a T trigger in that list - HMRC can collect the charge by reducing the number in your code, but the suffix is decided by the rules above. For scale, someone with adjusted net income of £75,000 in 2026/27 pays a charge of about £1,054 with one child, or £1,752 with two.

When you'll see T suffix

Your income is above £100,000 and HMRC has tapered your Personal Allowance, but not all the way to a K code (PAYE11045).
Your code includes car fuel or van fuel benefit (PAYE11045).
You asked HMRC for a T suffix - PAYE11045 lists an individual request as a reason, and HMRC can set it as a permanent suffix on your record (PAYE11076).
A second job or pension that is given part of your allowance, where the code is not BR or a D or K code (PAYE11045).
Less common items: a charitable donation adjustment, a very small net allowance, or older Married Couple's Allowance cases for people born before 6 April 1935 (PAYE11045).

What to do if you have a T suffix code

Verify the calculation: log in to Personal Tax Account → Tax Code section → "How we calculated your tax code". The breakdown explains every adjustment.
If the T suffix is unexpected or the numeric portion seems wrong: call HMRC on 0300 200 3300. Have your latest tax-code notice (P2) to hand.
Taper T codes: if your income for the year will end up lower or higher than HMRC's estimate (a bonus, a pay rise, or pension contributions that reduce adjusted net income), update the estimate in your Personal Tax Account so the tapered allowance in the code is right.
If you expected a Marriage Allowance code and see T instead, check the letter again: the recipient should be on M (e.g. 1383M) and the partner who transferred on N (e.g. 1131N).

Worked example

A salary of £110,000 is £10,000 over the £100,000 taper threshold, so the Personal Allowance loses £5,000 (£1 for every £2) and falls from £12,570 to £7,570. The code becomes 757T: the number is the tapered allowance divided by 10, and the T tells the employer not to uplift it automatically if the allowance changes, because HMRC has to recalculate the taper first. PAYE works exactly as it would on 757L.

Want to see the numbers for your own salary? Use the salary calculator and pick 2026/27 to see how T suffix interacts with your full take-home.

Frequently asked questions about T suffix

Is a T code worse than an L code?: No - PAYE calculates tax on a T code exactly as on an L code with the same number. The difference is that HMRC reviews T codes itself instead of telling employers to apply a Budget change to them automatically (PAYE Manual PAYE11075). The numeric portion is your tax-free amount divided by 10.
Why has my code changed from L to T?: One reason is that your expected income has gone above £100,000, so HMRC has tapered your Personal Allowance. Other triggers in HMRC's PAYE Manual (PAYE11045) include car or van fuel benefit, a request from you, and some second-job codes. Marriage Allowance is not one of them - it gives M or N. Your Personal Tax Account shows the "how we calculated your tax code" breakdown.
Does T mean I will owe tax at year-end?: Not necessarily. T just indicates special items in the calculation, not a likely underpayment. The numeric portion is HMRC's best estimate of your tax-free amount for the year - if it accurately reflects your circumstances, no year-end adjustment is needed. With a taper T code, the estimate of your income is the thing to check.
Can I switch from T back to L?: Yes, when the item that triggered T goes away - for example your income falls back below £100,000 so the taper no longer applies, or fuel benefit ends. HMRC then issues a new code, normally with the L suffix. If the T is only there because you asked for it, ask HMRC to remove the permanent suffix.

All UK tax codes →

Sources & further reading

All figures and definitions on this page reflect the 2026/27 UK tax year and are cross-checked against HMRC guidance.

HMRC — What your tax code means (official meanings for L, BR, D0, D1, K, 0T, NT, M, N, S, C, T)
HMRC — Income Tax rates and Personal Allowance (2026/27 bands and thresholds)
HMRC — Emergency tax codes (W1, M1 and X suffixes)
HMRC — Rates and thresholds for employers 2026 to 2027
HMRC — Your Personal Tax Account (check your current code and how it was calculated)
Our methodology & calculation sources →