A P45 is the form your UK employer gives you when you leave a job. It shows your leaving date, your total pay and tax from 6 April to the day you left, and your tax code, so your next employer can carry on taxing you correctly instead of guessing.
It's a small piece of paper (or a PDF) that does a lot of quiet work. Hand it over at your next job and your tax usually carries on smoothly. Lose it and you may well start the new job on an emergency tax code.
What's on a P45
| Detail | Why it matters |
|---|---|
| Leaving date | Tells your new employer and HMRC when the old job ended |
| Total pay and tax from 6 April to the date you left | Lets the new payroll carry on from the right running total |
| Tax code | Stops you being taxed on an emergency code |
| Personal details, including your National Insurance number | Matches you to your HMRC record |
What to do with your P45
- Starting a new job: give your P45 to your new employer, who uses it to work out how much tax you'll pay.
- Paper P45: give your new employer Parts 2 and 3, and keep Part 1A for yourself.
- Not working and claiming taxable benefits: give it to Jobcentre Plus instead.
- Keep a copy. You can also view and download pay and tax details for the last 5 tax years in your personal tax account or the HMRC app.
If you've lost your P45
Here's the detail most people don't expect: GOV.UK says if you've lost your P45, or your employer says they sent one and you never got it, you can't get a replacement. Instead, you fill in the starter checklist and give that to your new employer. If your old employer simply never gave you one, ask them for it, because without it you might pay the wrong amount of tax at your new job.
Why no P45 often means emergency tax
When your new employer pays you for the first time, they tell HMRC you've started. If they don't have your previous pay and tax details, GOV.UK says you'll be paid on an emergency tax code, which usually ends in W1, M1 or X. It works out tax on that week's or month's pay alone, as if you earned it every period of the year, so it can be wrong. HMRC usually updates the code once it has details from both employers, which can take up to 35 days. My guide to the Personal Allowance explains the tax-free amount the code is built on.
If your P45 is wrong
- Pay or tax figures wrong: ask your previous employer to correct them and send an amended P45. If they won't, tell HMRC through the check your Income Tax online service, and HMRC will ask the employer for the right figures.
- Tax code wrong: give the P45 to your new employer anyway. HMRC should correct your code automatically after your first pay.
- Personal details wrong: fill in the starter checklist and give it to your new employer with the P45.
For employers: what you must do when someone leaves
You must give an employee a P45 when they leave, and tell HMRC through payroll. GOV.UK's rules for the Full Payment Submission (FPS) are specific:
- Leaving in the current tax year: put their leaving date on their payroll record when you last pay them, and make deductions as normal in your next FPS.
- Paid for the last time now but leaving on or after the next 6 April: don't put the leaving date in the same FPS as the final payment. Include them in your first FPS of the new tax year with the leaving date and 0 in the pay and tax fields.
- Forgot to report a leaver: include them in your next FPS with the leaving date, using reason H if the payment date isn't the current one.
- Wrong leaving date reported: correct your payroll records, but don't report the amendment in the next FPS, as that can create a duplicate record.
If you're exempt from filing payroll online, you can order paper P45s from HMRC. Everyone else's UK payroll software usually produces the P45 when you mark someone as a leaver.
The starter checklist, when there's no P45
The starter checklist is HMRC's form for a new employee who hasn't got a P45. GOV.UK points you to it in three situations: you've lost your P45, you're starting your first job, or you're starting an additional job while keeping another. GOV.UK says you can fill it in instead of giving your new employer a P45, and it's also how you correct wrong personal details on a P45.
P45 versus P60
They're easy to mix up. A P45 is for leaving a job partway through the year. A P60 is the end-of-year summary you get if you're still working for the employer on 5 April. Unlike a P45, a lost P60 can be replaced by your employer.
My verdict
Photograph or save your P45 the day you get it, hand Parts 2 and 3 to your new employer before your first payday, and if it's gone, fill in the starter checklist straight away rather than waiting. Employers: issue it promptly and get the FPS leaving date right first time, because a duplicate record is far harder to unpick than a late form.
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At the end of the tax year you get a summary instead, which our guide to the year-end tax summary explains.
Frequently asked questions
What is a P45?
A form your employer gives you when you leave a job, showing your leaving date, your pay and tax from 6 April to the date you left, and your tax code.
Can I get a replacement P45?
No. GOV.UK says you can't get a replacement if you've lost your P45. Fill in the starter checklist for your new employer instead.
Which parts of the P45 do I give my new employer?
If you have a paper P45, give your new employer Parts 2 and 3 and keep Part 1A.
What happens if I start a new job without a P45?
You'll probably be put on an emergency tax code until HMRC gets your details, which can take up to 35 days.
Does my employer have to give me a P45?
Yes. GOV.UK says employers must give an employee a P45 when they leave.
Where can I see my old P45 details?
Your pay and tax details for the last 5 tax years are in your personal tax account and the HMRC app.
