How 0T works mechanically
0T tells your employer: - No personal allowance applied — your taxable income starts at £1 - Standard bands above £0: - 20% basic rate on the first £37,700 of taxable income - 40% higher rate on £37,700 to £125,140 - 45% additional rate above £125,140 - National Insurance applies separately under standard rules (unaffected by tax code)
Unlike emergency codes (W1/M1/X suffix), 0T is cumulative — your employer's payroll uses year-to-date totals to calculate the right amount.
Worked example — 0T on £30,000 sole income
Wrong code (0T): - Taxable income: £30,000 - All in basic rate band - Income Tax: £30,000 × 20% = £6,000 - Plus NI: ~£1,394 - Net: £30,000 − £6,000 − £1,394 = £22,606
Correct code (1257L): - Personal allowance: £12,570 - Taxable: £17,430 - Income Tax: £17,430 × 20% = £3,486 - Plus NI: same ~£1,394 - Net: £25,120
0T overpays £2,514 per year compared to 1257L. That's £210/month off your take-home until corrected.
Worked example — 0T on a £20,000 second job (correct)
If your main job earns £55,000 (uses personal allowance + most basic rate band) and you have a £20,000 second job:
- Main job: 1257L applied to £55,000 — uses all your allowance + most basic rate
- Second job: should be 0T (no allowance to spare, starts at £0)
- Second job tax: £20,000 × 20% = £4,000 (basic rate, since combined income is just at the higher-rate threshold)
Here 0T is correct — without it, you'd over-claim the allowance against two jobs and underpay tax, triggering a year-end correction from HMRC.
Why 0T appears
The three main causes:
1. New job without a P45
Your previous employer should have issued a P45 when you left. If you didn't give it to your new employer, the default is to ask you to complete an HMRC new-starter checklist instead. The checklist asks three questions; based on your answers, the employer applies one of:
- 1257L (Statement A — first job since 6 April)
- 1257L non-cumulative emergency (Statement B — this is your only/main job)
- BR (Statement C — you have other jobs/pensions)
If you don't complete the checklist or your answers don't fit, the employer often defaults to 0T.
2. Income above £125,140
The personal allowance tapers down between £100,000 and £125,140, fully tapered above. HMRC issues 0T (or a tailored T-suffix code with detailed allowance figure) once allowance is gone.
3. Multiple income sources
If HMRC's records show you have a primary source that's already using the allowance, your secondary source might get 0T instead of BR.
How to fix 0T if it's wrong
Fast resolution path:
- Log into your HMRC Personal Tax Account at gov.uk/personal-tax-account
- Confirm your current employment is listed correctly as your only/main job
- Provide any missing data (start date, previous employer, P45 details)
- HMRC re-issues a code to your employer (typically 2-4 weeks)
- Your next pay run applies the new code AND refunds year-to-date overpayment
If self-service doesn't resolve it, call HMRC on 0300 200 3300.
The longer 0T stays in place, the more overpaid tax accumulates. But it all comes back via PAYE once corrected — there's no permanent loss.
0T vs the other "no allowance" codes
| Code | Allowance | Rate structure | When right |
|---|---|---|---|
| 0T | £0 | Standard bands from £0 (20%/40%/45%) | Second income spanning bands; full taper applied |
| BR | £0 | Flat 20% on everything | Basic-rate second job |
| D0 | £0 | Flat 40% on everything | Higher-rate-only second income |
| D1 | £0 | Flat 45% on everything | Additional-rate-only second income |
| NT | £0 | No tax at all | Non-residence, treaty exemption, specific scenarios |
The difference is band progression. 0T uses normal bands; BR/D0/D1 are flat rates.
What 0T means for your payslip
You'll see "0T" or "0T Cumul" next to your tax code on your payslip. The deductions section will show:
- Income Tax at higher-than-1257L rates
- NI calculated normally (NI doesn't use tax code)
If you compare two months side-by-side and Income Tax looks 20-50% higher than expected for your salary, 0T is a likely cause.
Scotland and 0T
Scottish taxpayers see S0T instead of 0T. Same no-allowance rule; Scottish bands apply above £0: - 19% starter rate £0–£2,827 - 20% basic £2,827–£14,921 - 21% intermediate £14,921–£31,092 - 42% higher £31,092–£62,430 - 45% advanced £62,430–£125,140 - 48% top above £125,140 (Scottish 2026/27 bands)
A Scottish S0T on a £30,000 sole income is similarly wrong and similarly costly.
How long does 0T usually last?
Most 0T cases resolve within 4-8 weeks once you take action:
- Week 0: Notice the wrong code on your first or second payslip
- Week 1-2: Log into HMRC Personal Tax Account and update employment info
- Week 2-4: HMRC issues a corrected tax code to your employer
- Week 4-8: Employer applies the new code and refunds via PAYE
If you take no action, HMRC may auto-correct at the end of the tax year via the P800 process (April-October following year-end) — but you'd be without the refund for 6-12 months.
Practical checklist
- Check your payslip for "0T" tax code
- Run your salary through the tax code checker to see the cost difference
- Log into HMRC Personal Tax Account to confirm employment details
- Complete missing data (P45, start date, statement of employment status)
- Wait 2-4 weeks for the corrected code to land
- Verify next payslip shows correct code and any refund
In short
Tax code 0T applies no personal allowance with standard band progression — usually a temporary code after a new job without P45. On a sole income it costs ~£2,500/year extra in tax (for a £30,000 earner); fixes in 2-4 weeks via Personal Tax Account. For broader context see tax codes hub → and how to correct a tax code →.