What is a UTR?

How do you get a UTR, and what is it for?

HMRC issues one automatically when you register for Self Assessment, or when a limited company is formed at Companies House. It arrives by post within a couple of weeks, and it is yours for life — a sole trader who stops trading and starts again years later uses the same number.

An individual and a company each have their own. A director who is also self-employed therefore has two: a personal UTR for their own Self Assessment, and the company's UTR for Corporation Tax. They are not interchangeable, and putting the wrong one on a form is a common cause of returns going astray.

It is not the same as a National Insurance number, which identifies you for contributions and benefits, or a VAT number, which identifies a VAT registration. HMRC will ask for the UTR on every Self Assessment or Corporation Tax letter, and an accountant needs it to be authorised to act for you.

What does it look like in practice?

A bricklayer starts subcontracting for a builder. Before the builder can pay him, they must verify him with HMRC under the Construction Industry Scheme, and the verification is done using his UTR. Without one, the builder is required to deduct tax from his payments at the higher CIS rate rather than the standard one, on every job, until it is sorted out.

So he registers for Self Assessment on the first day, gets his UTR by post two weeks later, and registers for CIS with it. The builder verifies him, the standard deduction applies, and the deductions are set against his tax bill on the Self Assessment return that carries the same number.

What if you have lost it?

It is printed on any Self Assessment letter, the front of a tax return, and in the HMRC online account. If none of those are to hand, HMRC will send it again by post, to the address it holds — which is why keeping that address current matters. It is never given out over the phone or by email, to anyone.