A P45 is a document an employer gives an employee when they leave a job, showing pay and tax deducted so far in the tax year. It is used by the new employer or by HMRC to make sure the right amount of tax is deducted going forward.
Starting a new job without one
If a new employee cannot provide a P45, the employer usually asks them to complete a starter checklist instead, which gathers similar information so an appropriate tax code can be applied until HMRC issues an updated one.
Tax rules depend on individual circumstances and can change. This glossary is general information rather than personalised tax advice.