P45 Box Guide — Every Section Explained
Your P45 (Details of employee leaving work) is issued by your old employer on or shortly after your last day. It comes in four parts and feeds your new employer's PAYE. This guide walks through the four parts and the key boxes — what each means, what to hand to your new employer, and how to avoid emergency tax.
At year end? See the P60 Box Guide for the End of Year Certificate.
P45 Parts 1, 1A, 2 and 3
A P45 comes in four parts. Part 1 goes to HMRC from your old employer; Part 1A is yours to keep; Parts 2 and 3 go to your new employer.
P45 Box 5 — Student Loan deductions
Ticked if you had Plan 1, 2, 4, 5 or Postgraduate loan deductions at the time of leaving. Your new employer continues deductions from day one.
P45 Box 6 — Tax code at leaving date
Your PAYE tax code as at your last day. If followed by W1 or M1, it's non-cumulative — the new employer should not apply earlier pay/tax to your new employment.
P45 Box 8 — Total pay / tax to date
Cumulative pay and PAYE income tax from this employer for the tax year up to your leaving date. Your new employer uses these to run cumulative PAYE.
Starting a new job? Make sure you give Parts 2 and 3 of your P45 to the new employer before your first payday. Use the tax code checker to verify the code in Box 6, and the take-home pay calculator to estimate your first paycheck on the correct code.
Sources
P45 structure per HMRC PAYE forms guidance. Thresholds and tax codes current for 2025/26.