What Is a P45?
A P45 is a document your employer gives you when you leave a job. It summarises how much you've been paid and how much tax has been deducted from the start of the tax year up to your leaving date. Your employer is legally required to provide one, and it plays a crucial role in making sure you pay the right amount of tax in your next job.
The name comes from the original HMRC form number. Although the process is now handled electronically between employers and HMRC, the term P45 has stuck and you'll still receive a version of it when you leave employment.
What Information Does a P45 Show?
A P45 is split into multiple parts, and each contains the same core information:
- Your employer's PAYE reference — the unique reference number HMRC uses to identify your employer's payroll
- Your tax code — the tax code in use at the time you left, which your new employer will use to deduct the correct amount of tax
- Your total pay to date — your gross taxable earnings from 6 April up to your leaving date, not including any tax-free amounts
- Total tax paid to date — the total income tax deducted from your pay during the current tax year up to your leaving date
- Your National Insurance number — your unique identifier used by HMRC
- Your leaving date — the exact date your employment ended
The P45 comes in four parts:
- Part 1 — sent directly to HMRC by your employer (you never see this)
- Part 1A — this is your personal copy to keep for your own records
- Part 2 — you give this to your new employer, or to Jobcentre Plus if you're claiming benefits
- Part 3 — you also give this to your new employer
Important: Never throw away Part 1A. It's your proof of earnings and tax paid, and you may need it if there's ever a dispute about your tax or if you need to file a Self Assessment return.
When Do You Get a P45?
Your employer should give you your P45 on or shortly after your last day of work. There's no fixed deadline in law like there is for the P60, but HMRC expects employers to provide it promptly.
In practice, most employers issue the P45 on your final day or within a week or two of your leaving date, as it can only be produced once your final pay has been processed through the payroll system.
If your employer is dragging their feet, chase them. You're entitled to a P45 and they're obliged to provide one. If they refuse or go out of business, contact HMRC on 0300 200 3300 for help.
What To Do With Your P45
When you start a new job, hand Parts 2 and 3 of your P45 to your new employer. They'll use the information to set you up on the correct tax code and ensure you're not overtaxed or undertaxed going forward.
Your new employer sends the details to HMRC, and your tax record is updated so that your cumulative pay and tax carry over seamlessly. This means you continue to benefit from your personal allowance without interruption.
Keep Part 1A for yourself. File it somewhere safe alongside your payslips and P60s. You may need it when completing a Self Assessment tax return, applying for a mortgage, or checking that your tax for the year was calculated correctly.
What Happens Without a P45?
If you start a new job without a P45, your new employer won't know how much you've earned or paid in tax so far this year. To deal with this, they'll ask you to complete a Starter Checklist (formerly called a P46).
The Starter Checklist asks whether this is your first job since 6 April, whether you have another job, or whether you're receiving a pension. Based on your answers, your employer will assign a tax code.
In many cases, you'll be placed on an emergency tax code. This means your tax is calculated on a non-cumulative basis (marked as W1 or M1), which ignores what you've earned earlier in the year. The result is often that you pay more tax than you should in the short term.
Don't panic: Emergency tax is temporary. Once HMRC receives your details and updates your tax code, your employer will adjust your tax automatically. Any overpayment is usually corrected within a few pay periods, or you can reclaim it through HMRC.
P45 vs P60 — What's the Difference?
The two forms serve different purposes and are issued at different times:
- A P45 is given when you leave a job. It covers the period from 6 April to your leaving date and helps your next employer set your tax correctly.
- A P60 is given at the end of the tax year (by 31 May). It summarises your total pay and tax for the full year with that employer.
If you leave a job partway through the tax year, you get a P45 from that employer. If you're still employed on 5 April, you get a P60. You won't get both from the same employer for the same period.
If you changed jobs during the tax year, you'll have a P45 from your old employer and a P60 from your new employer (assuming you're still there on 5 April). Together, these documents cover your full tax year.
Related Guides
Learn more about your pay and tax with these guides:
- How to Read Your Payslip — understand every line on your monthly payslip
- How Tax Codes Work — what your tax code means and why it matters
- P60 Explained — what you get at the end of the tax year
- Take Home Pay Calculator — check exactly what you'll earn after tax
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