P45 Explained: Stop Paying Emergency Tax
Every time you leave a job you get a P45. It is the key document that stops your next employer putting you on emergency tax. Here is exactly what it is, what each part does, and what to do when things go wrong.
The 4 parts of a P45 — what each one does
A P45 is divided into four parts, each with a specific purpose. Your old employer fills in all the information; you only handle Parts 1A, 2, and 3.
| Part | Who gets it | What it contains | What to do with it |
|---|---|---|---|
| Part 1 | HMRC (sent by employer) | Employer PAYE reference, your NI number, leaving date, final tax code | Your employer sends this — you never see it |
| Part 1A | You (keep) | Same as Part 1 — your personal copy | File it safely with your tax records |
| Part 2 | New employer | Year-to-date gross pay and tax paid | Give to new employer when you start |
| Part 3 | New employer | Duplicate of Part 2 for payroll setup | Give to new employer alongside Part 2 |
Starter Checklist — the P45 replacement
If you start a new job without a P45 (lost it, first job, or employer hasn't issued it yet), your new employer will ask you to complete a Starter Checklist. You must tick one of three statements:
This is my first job since last 6 April and I have not been receiving taxable Jobseeker's Allowance, Employment and Support Allowance, taxable Incapacity Benefit, State Pension or occupational pension.
→ Resulting tax code: 1257L — full personal allowance, no emergency
This is now my only job, but since last 6 April I have had another job, or received taxable JSA, ESA, Incapacity Benefit, or a State Pension or occupational pension.
→ Resulting tax code: 1257L W1/M1 — week/month 1 basis (may overpay temporarily)
I have another job or am receiving a State Pension or occupational pension.
→ Resulting tax code: BR — basic rate 20% on all earnings, no personal allowance for this job
What a P45 shows — reading it line by line
Your P45 contains several key pieces of information:
- Box A — Employer PAYE reference: Your former employer's unique tax reference, in the format 123/AB456. Your new employer needs this for HMRC records.
- Box B — Your NI Number: Your National Insurance number (AB123456C format). This ties your employment record to your HMRC account.
- Box C — Tax code at leaving: The tax code you were on when you left. Ideally 1257L. Emergency codes (W1/M1, BR, 0T) here mean you may have overpaid tax.
- Box D — Leaving date: Your final day of employment. Used by HMRC to close your payroll record with that employer.
- Box E — Pay in this employment: Your year-to-date gross pay from 6 April to your leaving date — crucial for your new employer to calculate your tax correctly.
- Box F — Total tax in this employment: Total PAYE tax paid year-to-date. If this is unusually high, you may be owed a refund.
P45 vs P60 — key differences
| P45 | P60 | |
|---|---|---|
| When issued | When you leave a job | End of each tax year (by 31 May) |
| Who gets one | Everyone who leaves a job | Only those still employed on 5 April |
| Period covered | 6 April to your leaving date | Full tax year: 6 April to 5 April |
| How many per year | One per job you leave | One per employer you have at year end |
| Main use | Setting tax code at new job | Checking annual tax / proof of income |
| Can you get a replacement | No | Yes — your employer can reissue |
What to do if your employer won't give you a P45
It is a legal requirement for employers to issue a P45 when employment ends. If yours is refusing or not responding, follow these steps:
- Send a written request (email is fine, keep a record) asking for your P45 within a specific timeframe (e.g., 7 days).
- Inform your new employer you don't have a P45 and complete a Starter Checklist so you are not on emergency tax in the meantime.
- If the employer still refuses after a week, report the issue to HMRC by calling 0300 200 3200 or using the HMRC employer non-compliance reporting route online.
- HMRC can contact the employer directly and require them to issue the P45. They can also issue penalties to the employer for non-compliance.
- Request your year-to-date pay and tax figures directly — you are entitled to this information. Log in to your Personal Tax Account at gov.uk for your employment history and estimated figures.
Been put on emergency tax?
Emergency tax codes like W1, M1 or BR can mean you are overpaying hundreds of pounds. Find out how to claim it back.