The first payslip — what determines your code
Two paths into a new job:
Path 1 — With P45
You give your new employer the P45 from your previous job. The P45 contains: - Your tax code at the date of leaving - Year-to-date taxable pay - Year-to-date tax deducted
Your new employer's payroll uses the P45's tax code and continues year-to-date totals. You're effectively continuing the same tax position with a new employer.
Result: typically 1257L cumulative immediately, correct tax from first payslip.
Path 2 — Without P45 (new-starter checklist)
If you didn't give a P45 (lost it, previous job didn't issue, gap between jobs), your new employer asks you to complete an HMRC new-starter checklist.
The checklist asks you to pick one statement:
Statement A: "This is my first job since 6 April. I have not been receiving a state pension, occupational pension or social security benefit." - Result: code 1257L cumulative (assumes you have all your annual allowance to use)
Statement B: "This is my only job, but since 6 April I have had another job/pension/benefit." - Result: code 1257L W1/M1/X (non-cumulative, allowance applied per period — protects against double-claiming allowance you may have already used)
Statement C: "I have another job/pension." - Result: code BR (basic rate, no allowance — assumes other job is using your allowance)
Didn't complete the checklist: code defaults to 0T (no allowance, standard bands).
Why employers must use HMRC's defaults
When HMRC doesn't have full data on your year-to-date earnings: - It can't issue a cumulative tax code with confidence - It can't risk over-claiming your personal allowance (which would mean owing tax later) - Default to a "safe" code (emergency basis or BR) and let cumulative code arrive when data is in place
Within 4-8 weeks of starting, HMRC processes: - Your P45 (if you provided one) - Your new-starter checklist response - Your previous employer's RTI submissions - Any other PAYE income sources
Then HMRC issues a cumulative tax code to your new employer. The next pay run applies the new code AND catches up the year-to-date position.
Worked example — Statement A on £35,000 start in October
- Job started 1 October 2026
- Annual gross £35,000 → monthly £2,917
- Statement A → code 1257L cumulative
October payslip: - October is month 7 of the tax year (April-March) - You've had 6 months of zero employment income (according to your statement) - HMRC's cumulative calculation: year-to-date allowance £12,570 × 7/12 = £7,332 - Year-to-date earnings: £2,917 (this month only) - Below year-to-date allowance → £0 tax for October - Possible: small refund if HMRC's records had any over-deduction
November payslip: - Year-to-date allowance: £8,380 - Year-to-date earnings: £5,834 - Still below allowance → £0 tax
December payslip: - YTD allowance: £9,428 - YTD earnings: £8,751 - Still below → £0 tax
January payslip: - YTD allowance: £10,475 - YTD earnings: £11,668 - Above allowance by £1,193 → 20% × £1,193 = £239 tax - Then ongoing months: ~£250-£300/month tax
This is the "cumulative catch-up" pattern. Statement A is correct when you genuinely had no taxable earnings earlier in the year.
Worked example — Statement C on £35,000 start in October
Same start date and salary, but Statement C (other job/pension exists).
Code: BR (basic rate, no allowance)
October payslip: - Gross £2,917 - Tax 20% × £2,917 = £583
November-March: same. Total tax for the year (Oct-Mar): £3,498
If this turns out to be wrong (you don't actually have another job using your allowance), HMRC's year-end P800 calculates the overpayment and refunds. Or you can correct mid-year via Personal Tax Account.
When emergency codes resolve
Most new-job emergency codes resolve in 1-3 pay periods. The pattern:
| Pay run | Likely code | Notes |
|---|---|---|
| 1 (first) | 1257L W1/M1/X or BR or 0T | Per starter checklist |
| 2 | Same as run 1 | HMRC still processing |
| 3 | Often switched to 1257L cumulative | HMRC has caught up |
| 4+ | 1257L cumulative | Steady state |
For monthly-paid workers: usually resolved by month 3 or 4. For weekly-paid workers: usually by week 6-8.
What to do if emergency code persists past 8 weeks
- Log into HMRC Personal Tax Account at gov.uk/personal-tax-account
- Confirm your new job is listed correctly with start date
- Verify previous employment is shown (P45 data submitted)
- Update any missing fields (gap year, time abroad, etc.)
- Wait 2-4 weeks for HMRC to issue corrected code
If self-service doesn't help, call HMRC on 0300 200 3300.
The P45 you receive when you leave
When you leave a job: - Your employer issues a P45 within ~14 days - It has parts 1A, 2, and 3 - You give parts 2 and 3 to your new employer; keep 1A for your records
If you don't receive a P45 within a month of leaving, chase your previous employer's HR.
Self-employed transitioning to PAYE
If you've been self-employed and now starting your first PAYE job: - You don't have a P45 from a previous PAYE job - Complete the new-starter checklist with Statement A (no PAYE employment this tax year) - Your tax code is 1257L cumulative - Self-employment income for the same tax year is reported separately via Self Assessment
The PAYE income and self-employment income are reconciled annually in your SA return.
What to verify on your first payslip
- Tax code matches what you'd expect (1257L or one of the variants)
- Income tax deduction is reasonable for your salary
- NI is calculated correctly (8% above £242/week threshold)
- Net pay matches your expected take-home
Use the tax code checker → for verification.
Practical checklist
- Provide your P45 to your new employer if you have one
- If no P45, complete the new-starter checklist accurately
- Check your first payslip for the tax code applied
- Run the code through the tax code checker to confirm deduction is right
- Wait 2-3 pay periods for the steady-state cumulative code
- If still on emergency at 8 weeks, action via Personal Tax Account
- Overpayment refunds automatically when cumulative code applies
In short
Your tax code in a new job depends on whether you provided a P45. With P45: correct code from day one. Without: emergency code (W1/M1/X/0T or BR) until HMRC has full data — usually 4-8 weeks. Self-corrects automatically; any overpayment refunds via PAYE. For broader context see emergency tax → and tax codes hub →.