P Documents & Refunds
P45 Explained: Stop overpaying emergency tax
Every time you leave a job, you get a P45. It's the key to making sure your next employer doesn't put you on an emergency tax code. Here's exactly what to do with it.
What is a P45?
A P45 is a form given to you by your employer when you stop working for them. It shows how much tax you've paid on your salary so far in the tax year (6 April to 5 April).
When you start a new job, your new employer uses the information on your P45 to put you on the correct tax code.
The 4 parts of a P45
A P45 comes in 4 parts (Part 1, Part 1A, Part 2 and Part 3):
- Part 1: Your old employer sends this to HMRC.
- Part 1A: You keep this for your own records.
- Part 2 and Part 3: You give these to your new employer.
What happens if you don't have one?
If you don't give your new employer a P45, they will ask you to fill out a Starter Checklist (previously known as a P46). If you don't complete this, you will likely be put on an emergency tax code (such as W1/M1), which often results in paying too much tax temporarily.
Interactive: Will I pay emergency tax?
Do you have a P45 to give your new employer?
- ✅ Yes → You'll be on the right tax code. No emergency tax!
- ❌ No, but I filled out a Starter Checklist → You should be put on the standard tax code (usually 1257L).
- ❌ No, and I haven't done a Starter Checklist → ⚠️ You will be put on emergency tax.
What to do if your employer won't give you one
It is a legal requirement for your employer to give you a P45. If they refuse, keep asking. In the meantime, use the Starter Checklist for your new job so your pay isn't affected. You can also report the former employer to HMRC if they consistently refuse.