What Is a P45?
Your complete guide to the P45 form — what it shows, what to do with it when you change jobs, and how to avoid or recover emergency tax.
What is a P45?
A P45 is a document your employer must give you when you stop working for them. It is a legal requirement — employers must issue it on or before your last payday.
The P45 has four parts:
| Part | Goes to | Purpose |
|---|---|---|
| Part 1 | HMRC (via employer) | Your employer sends this electronically |
| Part 1A | You | Keep for your records |
| Part 2 | New employer | Give to your new employer |
| Part 3 | New employer | Also give to your new employer |
The P45 shows your tax code, your total gross pay so far in the tax year (6 April to present), and the total Income Tax deducted. Your new employer uses this to continue deducting the right amount of tax for the rest of the year.
What to do with your P45 when starting a new job
- Give Parts 2 and 3 to your new employer as soon as possible — ideally on your first day
- Keep Part 1A for your own records
- Your new employer submits the information to HMRC via RTI (Real Time Information) payroll
- HMRC confirms your tax code and your employer applies it from your next pay date
- If your tax code is wrong, contact HMRC — do not rely on your employer to sort it
No P45? You may be put on emergency tax
If you start a new job without a P45, your employer will use a Starter Checklist to estimate your tax code. You will typically be placed on:
Emergency tax usually sorts itself out within 1–3 pay periods once HMRC receives your starter details. Any tax overpaid is refunded through payroll automatically. If not, you can claim directly from HMRC.
How much could you overpay on emergency tax (BR code)?
Based on a single month of gross pay at code BR vs the correct 1257L tax code. Assumes this is your only income and you have not yet used your Personal Allowance.
| Monthly gross | Tax at BR (20%) | Correct tax (1257L) | Overpaid |
|---|---|---|---|
| £2,000 | £397 | £87 | £310 |
| £2,500 | £500 | £191 | £309 |
| £3,000 | £600 | £286 | £314 |
| £3,500 | £700 | £381 | £319 |
| £4,000 | £800 | £476 | £324 |
Approximations — actual tax depends on cumulative pay and whether any allowance has been used. See emergency tax guide for full worked examples.
How to reclaim overpaid emergency tax
If you are still employed and the correct code has been applied, HMRC will usually refund automatically through payroll. If not:
- Online: Use your HMRC Personal Tax Account at gov.uk/personal-tax-account
- By phone: Call HMRC on 0300 200 3300 (Monday to Friday, 8am–6pm)
- If you have left a job: Use form P50Z (stopped work) or P85 (leaving the UK)
- Self Assessment: Claim it through your tax return if you complete one
HMRC has 4 years to process repayments. Most refunds arrive within 5–10 working days by bank transfer if requested online.
P45 and your tax code
Your P45 carries your tax code from your previous employer. Common codes include 1257L (standard — Personal Allowance of £12,570), 1257L W1/M1 (emergency), and BR (basic rate, no allowance). If you had a non-standard code at your previous job (for example because of a company car or untaxed income), that code will appear on your P45.
Your new employer must apply the code from your P45, not guess. If HMRC then sends an updated code, the employer applies that instead. Always check your first payslip to confirm the code is correct.
Starting a new job at the beginning of the tax year
If you change jobs in April (the start of the tax year), your P45 from your old job will show zero gross pay and zero tax — because you had not been paid in the new year yet. This is normal. Simply give Parts 2 and 3 to your new employer and they will apply the tax code shown.
Frequently asked questions
What is a P45 in the UK?
A P45 is a form you receive from your employer when you leave a job. It shows your tax code, gross pay earned so far in the tax year, and the amount of Income Tax deducted. Parts 2 and 3 go to your new employer; Part 1A is yours to keep.
What happens if I do not have a P45 when starting a new job?
Your new employer will ask you to complete a Starter Checklist. Based on your answers, you may be placed on an emergency tax code (1257L W1/M1 or BR), which can cause you to overpay tax until HMRC issues the correct code.
How long does it take for emergency tax to be sorted?
Usually within 1 to 3 payslips once your employer has submitted your starter details to HMRC. Any overpaid tax is typically refunded through payroll automatically.
Can I get a replacement P45 if I have lost it?
No — your employer cannot issue a duplicate P45. Use a Starter Checklist with your new employer instead. HMRC can provide historical tax information through your Personal Tax Account.
What is the difference between a P45 and a P60?
A P45 is issued when you leave a job mid-year. A P60 is issued at the end of each tax year and covers your full year's earnings. You only get a P60 if you are still employed on 5 April. See our P60 guide for more.