What does the T suffix on my tax code mean?

The T suffix means HMRC has flagged your record for manual review — usually because your Personal Allowance is non-standard (e.g. tapered due to high income, or adjusted for a complex BIK history). The tax PAYE deducts under a T code is calculated the same way as the equivalent L code; the T just affects the administrative review.

Is a T-suffix tax code bad?

No — by itself it doesn't mean anything is wrong. It just means HMRC wants to keep your record under manual review. T codes are more likely to be inaccurate than auto-rolled L codes because they involve manual adjustments, so it's worth checking the underlying figures on your P2 coding notice.

Why does my tax code have a T instead of an L?

Most commonly: your income is above £100,000 (PA taper applies), or you have a complex benefit-in-kind situation. Less common: Marriage Allowance recently changed, you transitioned between employment and self-employment, or you have multiple income sources being reconciled. The P2 coding notice explains the specific reason.

Why does my tax code end with T?

Last reviewed by the UK Tax Drag editorial team · 12 May 2026 · How we review · Next review due 12 May 2027 · See what changed · Report an error

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A T-suffix tax code (e.g. 1257T, 1131T, 0T) calculates tax the same way as the equivalent L-suffix code, but the T flag tells HMRC to keep your record under manual review. Usually applied to high earners whose Personal Allowance is being tapered, employees with complex benefit-in-kind histories, or anyone who has requested specific PA confirmation.

How T-suffix differs from L-suffix

	L-suffix (e.g. 1257L)	T-suffix (e.g. 1257T)
Calculation method	Standard PA	Standard PA
Allowance applied	Number × 10	Number × 10
HMRC review status	Automatic	Manual review
Code updates each tax year	Auto-rolls each April	Reviewed before rolling
Indicates anything wrong?	No	Not necessarily — just complex

So the actual tax PAYE deducts under 1257T is identical to 1257L on the same gross pay. The difference is administrative: HMRC has noted your record for review and won’t auto-roll the code without confirmation.

Common reasons for a T-suffix

High earner with tapered Personal Allowance. If your income is above £100,000 and your PA is partially tapered, HMRC uses a T-suffix to flag the position. E.g. someone earning £110,000 would have £7,570 of PA (£12,570 − £5,000 taper), giving code 757T.
Complex benefit-in-kind history. If you had multiple BIK changes during the year (e.g. car returned mid-year, new BIK started), HMRC marks the code T to ensure it’s correctly reconciled.
Marriage Allowance recently claimed or removed. Especially if the timing is mid-year.
You requested PA confirmation. If you asked HMRC to confirm a non-standard PA (e.g. blind person’s allowance, age-related allowance for some older taxpayers), the code may show T while under review.
Multiple income sources being reconciled. Especially when you transition from employment to self-employment or vice versa.
HMRC ongoing enquiry. Rare — if HMRC is investigating your tax affairs, they may use T to flag the record.

Worked example — 757T on a £110,000 salary

You earn £110,000 a year. Your Personal Allowance is tapered to £7,570 (lost £5,000 of PA because income is £10,000 over the £100,000 trigger).

Component	Annual
Gross salary	£110,000
Tapered Personal Allowance (under code 757T)	£7,570
Taxable income	£102,430
Basic rate (20% × £37,700)	£7,540
Higher rate (40% × £64,730)	£25,892
Total income tax	£33,432
Employee NI	£4,210
Take-home	£72,358

The T-suffix prompts HMRC to verify next April that the £7,570 figure is still appropriate (e.g. that you didn’t earn more or less, which would change the PA taper).

Is a T-suffix bad?

No — by itself, no. The T just means HMRC wants to keep an eye on your record. It does not mean you’re being investigated, audited, or under-paying tax.

However, T codes are more likely to be wrong than auto-rolled L codes — simply because they involve manual adjustments. Common errors:

PA taper based on outdated estimated income (e.g. if your pay rose, more PA should be tapered)
BIK figures not updated when benefits changed
Marriage Allowance amount not reflecting current status

It’s worth checking your P2 coding notice carefully when you have a T code, even if the tax deducted appears normal.

What to do if you have a T code

Action 1: Get your P2 coding noticeCheck your Personal Tax Account for the most recent P2. It explains the breakdown of the allowance.

Action 2: Verify the underlying figuresIf your code is 757T because of PA taper at £110k income, confirm you actually expect to earn £110k. If you’re going to earn more (e.g. £120k) or less (e.g. £95k), the code should be different and you should update HMRC.

Action 3: Consider salary sacrifice if appropriateFor T codes triggered by the 60% trap (income £100k-£125,140), pension salary sacrifice that brings adjusted net income below £100,000 restores the full PA and reverts the code to 1257L. The salary sacrifice decision framework walks through this.

Manage the 60% trap

If your T-suffix is driven by the £100k-£125,140 PA taper, the 60% tax trap guide and ANI calculator show how to manage it.

Open the 60% trap guide →

Other UK tax codes explained

Sources and methodology

T-suffix code rules from gov.uk/tax-codes. Personal Allowance taper from gov.uk/income-tax-rates. P2 coding notice format from HMRC PAYE Manual.

UK Tax Drag is not authorised by the Financial Conduct Authority and does not provide regulated financial advice — see the content disclaimer for the full position. The methodology page documents how every calculator is built and reviewed.

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