UTR (Unique Taxpayer Reference)

A Unique Taxpayer Reference (UTR) is the 10-digit number HMRC issues to identify you (or your company) for Self Assessment. Every person who files a return has one, and it stays with you for life — unlike a tax code, which can change every year.

You get a UTR automatically when you register for Self Assessment. HMRC posts it within about 10 working days of registration. It's on the welcome letter, on every Self Assessment reminder, on filed returns, and inside your HMRC online account under "Self Assessment details".

You'll need it to: log in to HMRC online, file a return, make a tax payment (it goes in the payment reference), authorise an accountant, apply for a CIS card, request a Time to Pay arrangement, or ring HMRC about anything Self Assessment related. Without it, HMRC can't identify you — so keep it somewhere safe and private, but not so safe you can't find it in January.

Companies have a separate Corporation Tax UTR (also 10 digits) issued by HMRC shortly after Companies House registration. It's different from your personal UTR. Don't mix them up when making payments — HMRC treats them as different taxpayers.

A UTR is sensitive-enough information to keep private — combined with other personal details it can be used in HMRC impersonation scams — but on its own it isn't a financial credential. Don't post it publicly; do share it freely with your accountant.

Related terms

• Self Assessment — HMRC's system for declaring income not taxed at source — filed annually by the self-employed, landlords, and many directors.
• Tax code — The code HMRC gives your employer so they know how much of your pay is tax-free under PAYE.
• Payments on account — HMRC advance tax payments — half your prior-year bill, due 31 January and 31 July.