How to find your UTR number
Where your 10-digit Unique Taxpayer Reference appears, the quickest ways to look it up online, and what to do if you can't find it anywhere.
Last checked 22 August 2026
Before you start
Any one of these gets you to your UTR in a couple of minutes.
Your Government Gateway user ID and password, for the online routes.
The HMRC app on your phone, if you've set it up.
Old post from HMRC — most Self Assessment letters have the UTR on them.
Check letters HMRC has already sent you
Your UTR is the 10-digit reference on almost everything HMRC sends about
Self Assessment: the welcome letter you got when you registered, notices
to file a return, statements of account, and payment reminders. It's
sometimes printed with a letter K on the end — the K isn't part of the
UTR itself, it just marks a payment reference.
Sign in to your personal tax account
The fastest online route. Sign in with your Government Gateway details,
open the Self Assessment section, and your UTR is shown at the top of
the page.
Sign in to your personal tax account →Or open the HMRC app
The HMRC app shows your UTR under Self Assessment once you've signed in.
If you already use the app, this is usually quicker than the website.
Get the HMRC app on GOV.UK →Ask HMRC to post it if you can't sign in
If you can't access the online account, ask HMRC for your UTR through
the Self Assessment helpline. For security they won't read it out over
the phone — they post it to the address on your record, which normally
takes up to two weeks.
Find a lost UTR on GOV.UK →Good to know
If your address has changed, update it with HMRC first — the letter
goes to whatever address they hold.
Use the right UTR for the right taxpayer
A limited company has its own UTR for Corporation Tax, posted to the
registered office shortly after incorporation, and a partnership has one
too — separate from each partner's personal UTR. Quoting the wrong one
is the usual reason a payment or return doesn't match up.
Common questions
UTRs, in practice
What does a UTR look like?
Ten digits, for example 1234567890. On payment references it appears
with a K at the end — 1234567890K — but forms that ask for your UTR
want just the ten digits.
Is my UTR the same as my National Insurance number?
No. Your National Insurance number identifies you across the benefits
and tax system; your UTR identifies your Self Assessment record. HMRC
forms often ask for both.
I've never had a UTR — where do I get one?
You get a UTR by registering for Self Assessment. It arrives by post
once HMRC has processed the registration.
Do I get a new UTR if I stop and start again?
No — your UTR stays with you for life. If you return to Self
Assessment, re-register quoting the UTR you already have.
Related guides
What people usually need a UTR for.
How to register for Self Assessment
Tell HMRC you need to send a tax return, pick the right registration form, and get your UTR before the 5 October deadline.Read the guide →
How to pay your Self Assessment tax bill
The ways to pay, how long each one takes to reach HMRC, and the dates your balancing payment and payments on account fall due.Read the guide →
Never hunt for a reference again.
Bookfolio keeps your business records, tax position, and HMRC filings in one place, so the numbers you need are there when HMRC asks for them.