Do You Need a P45 When You Leave a Job in 2026?

[SanOscar]

Yes, you absolutely need a P45 when you leave a job in the UK. It is a critical document issued by your employer when you stop working for them. Think of it as a summary of your earnings and tax contributions for the portion of the tax year you were employed there. Without it, your new employer cannot set up your correct tax code, which could lead to you being placed on an emergency tax code and paying significantly more Income Tax and National Insurance than you should.

The P45 is divided into four parts. Your employer gives you parts 1A, 2, and 3, while part 1 is sent directly to HM Revenue and Customs (HMRC). You then hand parts 2 and 3 to your next employer. This form contains your tax code, total pay to date, and total tax deducted to date. This data is vital for ensuring your new payroll runs smoothly from the first pay period.

If you lose your P45, you must inform your new employer. They will have you fill out a HMRC Starter Checklist (formerly known as a P46). This form asks about your previous employment and tax status. While it is a functional substitute, it can delay the correct tax code adjustment. In my experience, keeping your P45 safe is one of the most important administrative tasks when changing jobs. It prevents overpayment of tax and avoids the hassle of having to reclaim money from HMRC later. An efficient handover of this document is a sign of good employee onboarding practices within a company.

[Katelyn]

Oh, 100% yes. You need that P45. It’s not just a formality. If you don’t have it, your new employer will likely put you on an emergency tax code, which means you’ll pay way too much tax for the first few months. Then you’ll have to chase HMRC for a refund. It’s a massive headache. Just keep it in a safe place with your other important documents. It’s basically your tax history for that job.

[KylieLynn]

Yes, you do. It’s the standard document that closes out your old payroll and opens your new one. Handing over your P45 parts 2 and 3 is the cleanest way to ensure your tax code is accurate. If you don’t have one, you’ll complete a Starter Checklist. It works, but it’s not as efficient. Honestly, just ask your ex-employer for it. They are legally required to provide it.

[AsherAnn]

You definitely need it. I’ve seen so many people mess this up. Without a P45, your new employer lacks the data to calculate your tax-free allowance correctly. You’ll end up on a BR or 0T tax code, meaning you get taxed on all your income. That’s a big chunk of your salary gone. It’s much easier to just request the form when you resign. It’s a simple process that saves you a lot of money and time.

[SanAvery]

Yes, you need it. It’s the official record of your pay and tax for that job. Your new employer uses it to set your tax code and avoid overpaying tax. If you lose it, you can use a HMRC Starter Checklist, but the P45 is the preferred method. It’s a key part of employee offboarding. Honestly, just keep it. It’s a small piece of paper that solves a big problem.