Your company's UTR number: what it is, where to find it, and why HMRC needs it for every filing

A UTR — Unique Taxpayer Reference — is a 10-digit number that HMRC assigns to every entity registered for tax in the UK. Your UK limited company receives a corporation tax UTR when you register it for corporation tax with HMRC. It is entirely separate from your company number (which Companies House issues on incorporation) and from your VAT registration number (if you are VAT-registered). These three reference numbers are distinct, issued by different bodies, used for different purposes, and commonly confused by directors who are new to UK compliance.

Where to find your company's UTR: HMRC posts it in the first letter they send to your company after you register for corporation tax. This letter goes to your company's registered office address. If you have lost that letter, your UTR also appears on any previous CT600 corporation tax return, in your HMRC Online Services business tax account, and on any HMRC payment reference slip. If Fileminder is your accountant, we hold your UTR on file and use it on every CT600 and every payment on your behalf. If you are unsure, ask us.

When you need it: your UTR appears on every CT600 corporation tax return filed with HMRC, on every corporation tax payment (your payment reference is your UTR plus a suffix), on any HMRC correspondence about corporation tax enquiries, and when authorising your accountant as your agent with HMRC. Without the correct UTR, HMRC cannot match your payment or return to your company's tax record. Payments made without the correct reference end up unallocated, which HMRC treats as a missed payment — interest accrues even if the money was sent.

What to do if your company has no UTR: your company will not have a UTR if it has never been registered for corporation tax with HMRC. This is a separate registration from Companies House incorporation. You register at gov.uk/limited-company-formation/set-up-your-company-for-corporation-tax — it should be done within three months of starting to trade, or earlier. HMRC sends the UTR to your registered office, so make sure your registered office address is managed professionally (letters don't go unread or unforwarded). If you have been trading for some time without registering, HMRC may also have outstanding CT600 obligations against your company — this is worth checking before registration.

The personal vs company UTR distinction: if you also file UK self-assessment income tax returns as an individual, you have a personal UTR. It is entirely separate from your company's UTR. Both are 10-digit numbers in the same format, which causes confusion. Personal UTRs are used for income tax (self-assessment); company UTRs are for corporation tax. If you have both a personal UK income obligation and a UK company, you hold two different UTRs and must use the correct one for each type of filing and payment.