The P45 Form
A P45 is an official document issued by your employer when you leave a job. It acts as a formal record of your total taxable earnings and the exact amount of Income Tax deducted during the current tax year up to your final leaving date.
Providing this form to a new employer is critical to ensuring you are placed on the correct tax code from your very first payday.
What Is on a P45?
A P45 is broken down structurally into four distinct sections, each serving a specific administrative purpose:
| Section | Who It Is For | Purpose |
|---|---|---|
| Part 1 | Sent to HMRC | Your old employer sends this directly to HMRC to formally log your termination date. |
| Part 1A | Kept by You | This is your personal copy. Keep it safe as historical evidence for your personal tax records. |
| Part 2 | Given to New Employer | Handed to your new payroll department so they can log your year-to-date figures. |
| Part 3 | Given to New Employer | Used by your new employer to officially register you as a new starter on their payroll. |
How a P45 Affects Your New Job
Your P45 gives your new payroll team visibility over what tax has already been sliced from your income earlier in the tax year. This ensures they apply your remaining tax-free Personal Allowance incrementally across your new monthly or weekly pay packets.
If your P45 is accurate and provided on onboarding, it prevents your new employer from automatically dropping you onto an emergency tax code, which frequently triggers an unexpected spike in tax deductions.
What If You Do Not Have a P45?
If you are starting your very first job, taking on an additional second job, or your previous employer is delaying your paperwork, you will not have a P45.
In these scenarios, your new employer will instruct you to complete an online or paper Starter Checklist.
- The Setup: The Starter Checklist asks you basic questions regarding your current circumstances (e.g., whether you have another active job, receive a pension, or have an active student loan).
- The Tax Treatment: While HMRC processes this information, you may be placed on a temporary emergency tax code (such as
1257L W1or1257L M1).
Don't Panic: While emergency tax codes can cause you to pay too much tax on your first few payslips, HMRC will automatically reconcile your record once your starter information links up. Any overpaid tax will be calculated and refunded straight back through your future payroll cycles.
What If You Lose Your P45?
If you accidentally misplace your P45, your previous employer is legally unable to generate a duplicate copy for you. Instead, you must resolve the missing information using the following steps:
- Check Your Digital Account: You can log in to your HMRC Personal Tax Account or the official HMRC mobile app to view and print your exact year-to-date pay and tax figures.
- Complete the Checklist: Pass these figures onto your new employer, or simply fill out a fresh Starter Checklist to kickstart your new payroll record.
Key Points to Remember
- A P45 explicitly prevents you from being placed on a punishing emergency tax code at a new job.
- The form is divided into four parts—keep Part 1A for your personal archives.
- If a P45 is missing, filling out a Starter Checklist is the correct, official workaround.
- Lost P45s cannot be reissued by law, but your tax details can always be checked securely inside your HMRC Personal Tax Account.