When should my employer give me my P45?

On or shortly after your last day of employment. By law (PAYE Regulations 2003) it must be issued without unreasonable delay — typically within 1-2 weeks. If late, request it in writing; persistent failure is reportable to HMRC.

Can I keep my P45 if I'm not starting a new job immediately?

Yes — Part 1A is yours to keep. Parts 2 & 3 should be given to your next employer when you start work. If unemployed, send Parts 2 & 3 to Job Centre Plus to claim Universal Credit or Jobseeker's Allowance.

Does my P45 work for a new job in a different tax year?

No — the P45 is specific to the tax year of leaving. If you start a new job in the following tax year (after 5 April), the new employer uses the starter checklist.

Will I get a refund through my P45?

Possibly — if your old job overdeducted tax (e.g. cumulative coding adjusted late), the new employer's cumulative reconciliation refunds it. If unemployed at year-end, claim refund via P50 form or self-assessment.

What if my old employer hasn't given me a P45?

Contact them in writing. If still no response after 1-2 weeks, contact HMRC who can chase. Don't wait — without P45 your new employer applies emergency code, costing you £100s in temporary overpayment.

Do contractors / temps get a P45?

Yes — if they're employed (PAYE) by an agency or umbrella company. Self-employed contractors don't have a P45; they use self-assessment instead.

Does the P45 show NI?

Yes — year-to-date NI contributions are included. NI doesn't have the same cumulative reconciliation as income tax (it's calculated per pay period), but the figure is shown for record-keeping and pension purposes.

How long should I keep my P45?

At least 22 months after the end of the tax year (the standard HMRC retention period). For pension records, keep indefinitely in case of NI year disputes.

P45 Leaving Employer Tax Calculator UK 2025/26

How a P45 works in 2025/26

The P45 is the form your employer gives you when you leave a job. It records:

Total pay year-to-date in the current tax year.
Total tax deducted year-to-date.
Your tax code at leaving.
National Insurance year-to-date (separate calculations).
Date of leaving.

The P45 has multiple parts:

Part 1 — sent by your old employer to HMRC.
Part 1A — you keep this for your records.
Parts 2 & 3 — give to your new employer or send to Job Centre Plus if claiming benefits.

When you give your new employer parts 2 & 3, they enter your year-to-date pay and tax into payroll, applying your tax code on a cumulative basis. The next pay period reconciles automatically — if you've overpaid in your old job (e.g. due to a bonus boosting your YTD against insufficient YTD allowance), the new employer refunds via the new pay packet.

What happens without a P45

If you start a new job without a P45, the employer uses HMRC's starter checklist (replacing the old P46). You tick one of three statements:

Statement A — this is your first paid job since 6 April. Cumulative 1257L applied.
Statement B — this is now your only job, but you've had earnings since 6 April. Cumulative 1257L applied (HMRC will adjust if needed when they reconcile).
Statement C — you have another job or pension. BR (basic rate, no allowance) applied.

Without the P45 details, the new employer can't continue cumulative — they apply the code on a "current pay only" basis until HMRC catches up (typically 4-8 weeks).

If you've overpaid tax in the gap, the cumulative reconciliation refunds it in your first proper paycheck. If HMRC doesn't issue a cumulative code by year-end, file a P50 form (if unemployed) or self-assessment to claim the refund.

Three worked examples (UK 2025/26)

Example 1: Mid-year job switch with P45

Sarah leaves Job A on 30 September 2025 with year-to-date pay £20,000 and tax £1,800. Tax code 1257L. She starts Job B on 1 November 2025 at £45,000 annual.

Calculation: Job B uses P45 to continue cumulative. Tax week ~31 (October), her YTD allowance is £12,570 × (31/52) ≈ £7,494. YTD pay £20,000. YTD tax due: (£20,000 − £7,494) × 20% = £2,501. She's already paid £1,800, so November payslip deducts £701 plus the normal monthly tax. Future pay continues cumulative.

Example 2: Gap year without P45 — emergency tax

Tariq leaves Job A in May 2025 (P45 issued, total earned £4,000, tax £0). Doesn't work until October 2025 then loses P45. New employer uses starter checklist Statement A → cumulative 1257L.

Outcome: Cumulative on 1257L means his year-to-date pay (now £4,000) and YTD allowance (£8,380 by tax month 7) leaves him with significant unused allowance — the new employer's first paycheck would refund a lot of his already-deducted tax. Net tax due may be £0 for several months.

Example 3: Lost P45 + Statement C tick — overpayment

Diego loses his P45. Ticks Statement C ('I have another job') by mistake at his new employer. New employer applies BR.

Outcome: Diego pays 20% on every £ from day one — losing £2,514 of allowance for the rest of the year. He must contact HMRC, who issue 1257L cumulative once the misunderstanding is corrected. The first cumulative paycheck refunds the overpayment.

Common mistakes to avoid

Throwing away the P45 — keep Part 1A for records and give Parts 2 & 3 to next employer.
Filing Statement C when you've actually left your last job — gives BR and overpaid tax.
Failing to tell HMRC if you don't start a new job by year-end — file P50 to claim refund.
Not chasing the new employer's payroll if cumulative coding doesn't kick in — call HMRC at week 6-8.
Believing P45 lasts beyond 5 April — it's tax-year specific; new employer in next year uses it for the prior year only.
Confusing P45 (when leaving) with P60 (annual statement) and P11D (benefits).

When to use this calculator

Use this calculator when leaving a job — to estimate your year-to-date tax position and what the new employer should deduct. Useful for verifying the P45 figures match your understanding. Run again 1-2 months into the new job to confirm cumulative reconciliation has worked. Self-employed switching to employment should compare expected employed take-home with prior-year self-assessment.

Regional differences (Scotland, Wales, Northern Ireland)

Tax codes are issued by HMRC and apply to UK-wide employees. Scotland uses tax codes prefixed "S" (e.g. S1257L) to indicate Scottish income tax bands (Starter 19%, Basic 20%, Intermediate 21%, Higher 42%, Advanced 45%, Top 48%) — the numerical allowance portion is the same as rUK. Wales uses "C" (e.g. C1257L) for Welsh resident, but Welsh rates currently match UK. Northern Ireland uses standard UK codes throughout. The numerical part of the code (e.g. 1257 for £12,570 PA) is identical across the UK; only the prefix changes the band structure.

P45 Leaving Employer Tax Calculator — UK 2025/26