UK HMRC Forms Explained
Every UK HMRC form, reference number, and document you'll meet in the UK tax system — explained in plain English with practical guidance. P45, P60, P11D, NINO, UTR, SA100, plus the less-known forms (P85, P50, CWF1, P800) that matter when your circumstances change.
P45?
A P45 is the form your employer gives you when you leave a job. It records your earnings and tax paid in the current tax year up to your leaving date.…
P60?
A P60 is a year-end UK tax summary your employer must give you by 31 May after each tax year (which ends 5 April). It shows your total earnings, total…
P11D?
A P11D is a year-end UK form showing the cash value of any taxable benefits you receive on top of your salary — company car, private medical insurance…
National Insurance Number (NINO)?
Your National Insurance Number (NINO) is your unique UK tax and social security identifier — a 9-character code in the format AB123456C. It tracks you…
UTR Number?
A UTR (Unique Taxpayer Reference) is a 10-digit number HMRC assigns to anyone registered for self-assessment — sole traders, freelancers, landlords, c…
SA100 Self Assessment Form?
The SA100 is the main UK Self Assessment tax return form. It's the document that reports all your income, tax-deductible expenses, and tax paid to HMR…
P85? (Leaving the UK)
Form P85 is the UK form you complete when you're leaving the UK to live or work abroad permanently or for a long period. It tells HMRC you've left, so…
Starter Checklist (P46)?
The Starter Checklist (formerly P46) is the form you complete for a new UK employer when you don't have a P45 from your previous job. It captures basi…
P800?
A P800 is HMRC's annual tax calculation letter, sent if you've over- or under-paid tax during the year. If you owe HMRC, the P800 explains how much an…
CWF1 Form? (Self-Employed Registration)
Form CWF1 is the UK form for registering as self-employed with HMRC. It establishes your self-assessment record, generates your UTR, and starts your C…
P50? (Tax Refund When Stopping Work)
Form P50 is the UK form for claiming a tax refund when you've stopped working for at least 4 weeks and don't expect to work again in the current tax y…
Two reference numbers, three letter codes
Most UK taxpayers deal with two key reference numbers: NINO (National Insurance Number — for employment, NI, and State Pension) and UTR (Unique Taxpayer Reference — for self-assessment if you're self-employed or have other income). PAYE employees only need NINO; self-employed need both.
The three forms most UK employees see annually: P60 (year-end summary), P45 (when leaving a job), and P11D (if you have benefits-in-kind). The other forms only matter when circumstances change — leaving the UK, going self-employed, retiring, or HMRC reconciles your tax. Pair this guide with our UK tax codes explained for the full PAYE picture.
UK HMRC forms FAQs
What is a P45 and when do I need it? +
A P45 is the form your employer gives you when you leave a job. It shows your total earnings and tax paid in the current tax year. You give parts 2 and 3 to your new employer (or HMRC if not working) so they apply the correct tax code. Without a P45, you start on emergency tax codes (often M1/W1). Should arrive within 4 weeks of your last day.
What's a P60 and when do I get it? +
A P60 is the year-end summary of total pay and tax for the tax year, given by 31 May each year. You need it for tax returns, mortgage applications, claiming benefits, or proving income. Keep all P60s — HMRC recommends 22 months minimum, but mortgage lenders and HMRC investigations can ask for older ones. Digital P60s are valid since 2010.
What is a P11D and do I need to fill one? +
A P11D reports taxable benefits and expenses provided by your employer (company car, medical insurance, gym membership). You don't fill it — your employer does, by 6 July each year. You receive a copy. The tax on benefits is collected via your tax code. Check your P11D against what you actually received; errors are common.
When do I need to fill a Self Assessment tax return? +
If you're self-employed, a company director, earn over £150,000, have untaxed savings/dividend income over £10,000, sold property, or HMRC has sent you a notice. Deadline: 31 October paper, 31 January online for the previous tax year. Late filing fines start at £100. You can register and file at gov.uk/self-assessment.
What's a P87 form? +
A P87 is for claiming tax relief on employment expenses (mileage, professional subscriptions, work-from-home costs, uniforms). Use it if your total claim is under £2,500/year — otherwise file a Self Assessment. Online via gov.uk takes 8 weeks for most refunds. You can backdate up to 4 tax years.
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