What Is a P45? A Plain-Language Guide to the UK Leaving Tax Form

A job change can bring a strange mix of relief and loose ends. In this hypothetical scene, a worker has accepted a new role and is sorting through their final email from their former employer: a goodbye note, a last payslip, and an attachment labeled "P45." The name sounds more like a document code than something useful, so it is easy to set aside. But the new employer soon asks for it, and the worker wonders whether it affects their pay, taxes, or next steps. The good news is that a P45 is not a penalty or a problem to solve. It is a standard UK employment tax document that helps carry key payroll information forward after someone leaves a job.

What is a P45?

A P45 is a UK tax form an employer gives an employee when that employee stops working for them. The UK government lists the P45 among the forms employees receive to report taxable income, specifically when they leave an employer. GOV.UK explains the P45, P60, and P11D forms here. The form records tax and payroll information from the job that has ended, creating a handoff between the employee, the former employer, and, when applicable, the next employer.

A P45 is mainly relevant to people working under the UK's PAYE system, the process through which employers handle income tax through payroll. For a U.S.-based reader, it may help to think of a P45 as an end-of-employment tax record. It is not an exact equivalent of a U.S. W-2, but it serves a related purpose: providing employment and tax information after a worker leaves.

Why a P45 matters

Leaving a job does not erase the tax and payroll information connected to that job. A P45 documents what happened during the portion of the tax year when the employee worked for the former employer, and it carries that information forward rather than treating each job as a fully separate payroll event.

The form can be useful in several situations:

• Starting a new job: A new employer may use the information to help process payroll correctly.
• Keeping personal records: Employees can retain it as part of their employment and tax paperwork.
• Changing circumstances: It can be relevant when someone is between jobs or dealing with benefit-related administration.
• Checking payroll history: The information may help an employee compare records from their final pay period against what the employer reported.

What information does a P45 include?

According to Starling's overview of P45 and P60 forms, a P45 passes tax and payroll information from the former employer to the employee and, potentially, to a new employer. It generally reflects identifying details for the employee and former employer, the employee's tax code, and pay and tax figures tied to that period of work.

However, a P45 does not tell the whole story of every workplace deduction. Starling notes that P45s do not show National Insurance deductions or pension contributions. That is one reason it can be wise to keep a final payslip as well as the P45, since the payslip may contain deductions not shown on the P45.

When do you get a P45?

You receive a P45 after you stop working for an employer. That can happen for many reasons, including resignation, the end of a fixed-term role, retirement, dismissal, or a move to a different employer.

The document is tied to leaving that particular employment, not necessarily to leaving work altogether. Someone can receive a P45 from one employer and begin work somewhere else shortly afterward. This distinction matters for people who hold more than one job. A person may leave one role while continuing another, and in that case the P45 relates only to the employment that ended.

Why your new employer wants it, and what happens if you don't have one

When you start a new UK job, your employer typically uses your P45 to set up your payroll correctly under the PAYE system, including applying the right tax code for the rest of the tax year. This is standard PAYE practice, not a personalized calculation.

If you don't have a P45 when you start, most UK employers will ask you to complete a starter checklist instead. Without the information a P45 normally provides, a new employer may need to place you on a temporary or emergency tax code until your correct details are confirmed with HM Revenue and Customs. This does not mean something has gone wrong. It generally sorts itself out once accurate information is on file, though it can affect your pay in the short term. For specifics on your situation, GOV.UK is the most reliable starting point, and a tax adviser can help with anything unusual.

What should you do with a P45?

When you receive a P45, treat it as an important financial record. Start by checking it for obvious errors, such as a misspelled name or details that do not match your final pay records.

If you are starting a new job

Give it to your new employer promptly as part of onboarding. This helps them apply the correct tax information for the rest of the tax year. Keep a copy for yourself, whether it arrives electronically or on paper.

If you are not moving directly to another job

Keep the P45 with your other tax and employment paperwork. It may be useful while you organize your finances or handle administrative questions related to your change in employment. If you are unsure how it applies to your situation, use official guidance or seek qualified tax advice.

If something looks wrong

Contact the employer that issued the form and explain the issue clearly. Gather supporting records first, such as your final payslip, employment end date, and any payroll correspondence. A calm, specific question is usually more productive than a general request to "fix" the form.

P45 vs. P60: What is the difference?

A P45 and a P60 are both UK PAYE-related documents, but they cover different events. A P45 is issued when you leave an employer and captures information at the point employment ends. A P60 is a separate, year-end employment tax document. GOV.UK includes both in its explanation of forms employees may receive. See GOV.UK's overview of P45, P60, and P11D forms.

The simplest way to remember the difference: a P45 is about leaving a job, while a P60 is a year-end summary. Do not assume one replaces the other; the document you need depends on what you are trying to confirm.

A practical checklist before leaving a UK job

1. Save recent payslips. Your final payslip may show details not included on a P45, such as National Insurance or pension deductions.
2. Confirm your contact details. Make sure the employer can reach you if a payroll question comes up after you leave.
3. Watch for your P45. Ask how it will be delivered if the employer has not explained the process.
4. Review the information. Compare key details with your own records, including your leaving date and final pay.
5. Store documents securely. Keep digital copies in a protected location and retain any original paperwork.

For employers, the same principle applies: clear, accurate end-of-employment documentation supports a smoother transition for both the organization and the departing employee.

The key takeaway

Review your P45 for accuracy, keep it with your final payslip and other employment records, and give it to a new employer if requested. Doing so helps your new payroll get set up correctly and avoids unnecessary delays with your tax code.

Informational note: This article is provided for general informational purposes only and is not legal advice. It does not represent the advice or opinion of the website or organization on which it appears.