P45
UK tax glossary · Last reviewed: April 2026
A P45 summarises pay and tax deducted in the tax year up to your leaving date. Part 1 goes to HMRC; parts 2 and 3 go to you and your new employer.
Without a P45, your new employer may put you on an emergency tax code until HMRC updates your record. This commonly causes overpayment until the correct code is issued.
If you are starting a job but have no P45 (for example because you have been out of work, or this is your first job), complete a Starter Checklist (formerly called a P46). This tells your employer which tax code to use.
Worked example
Left job in October 2026. P45 shows pay to date: £18,000, tax paid: £1,086. New employer uses P45 to set tax code at 1257L cumulative — continuing year-to-date figures correctly. Without P45, new employer applies 1257L M1 (non-cumulative), potentially over-deducting until HMRC corrects it.
Common questions
What do I do if my employer refuses to give me a P45?
Your employer is legally obliged to provide a P45 when you leave. If they refuse or delay, contact HMRC directly — they can chase the employer and update your records manually.
Can I get a copy of a lost P45?
No. Unlike P60s, lost P45s cannot be reissued by former employers. Contact HMRC to discuss your options — they can update your tax record directly using the information they hold.
Related resources
TaxHelper provides general information based on published HMRC rates and guidance. It is not regulated financial or tax advice. For decisions involving significant sums, complex circumstances, or if you are unsure, speak to a qualified accountant or HMRC directly.