UTR numbers: What they are, how to apply, and how to find them

Key takeaways

• A Unique Taxpayer Reference (UTR) is a permanent 10-digit number HMRC issues to identify sole traders, partnerships, and limited companies — you need one before you can file a Self Assessment or Corporation Tax return.

• Around 300,000 taxpayers submit their Self Assessment returns in the very first week of the filing season alone, and missing the 5 October registration deadline can trigger late-notification penalties that are difficult to undo.

• High-street banks and domestic-only accounts such as Monzo, Starling, and Tide charge 2.75–3% FX markups and restrict multi-currency use, while Airwallex offers Global Accounts in 20+ currencies, 0% international transaction fees, corporate cards with built-in spending controls, and direct Xero and QuickBooks integration — cutting costs and complexity for UK businesses operating beyond sterling.

Missing your UTR creates real problems. HMRC can reject returns that don't contain a valid reference, and once a late-filing penalty lands, it's hard to undo.

For founders and sole traders, the bigger challenge is keeping several similar-looking identifiers straight at once — UTR, NI number, Company Registration Number, VAT number — without mixing up what each one actually does.

This guide explains what a UTR is, who needs one, how to apply, how to recover it if it goes missing, and what financial infrastructure to build once your compliance is sorted.

What is a UTR number?

A Unique Taxpayer Reference is a 10-digit number HMRC assigns to individuals and legal entities that need to file tax returns. It's confidential, permanent, and stays tied to that person or entity for the life of their tax record.

It doesn't change if you move address, update your trading name, or take a break from trading. Once HMRC assigns it, it identifies you in every return, payment, and piece of correspondence.

A standard UTR looks like this: 12345 67890. But, HMRC systems can also handle several legacy input variants:

• 10 digits, with or without spaces

• 13-digit versions, with or without spaces

• Sequences that start or end with the letter 'K' in certain service patterns

The 10-digit format is what you'll encounter in most day-to-day situations. The variations exist to accommodate legacy systems and reduce input errors on HMRC's electronic forms.

Who needs a UTR number?

Not everyone in the UK has one. HMRC issues UTRs to people and entities with specific tax obligations — not automatically to every UK resident.

Sole traders and self-employed professionals

If you earn more than £1,000 in gross trading income in a tax year, you'll generally need to register for Self Assessment. That registration triggers your personal UTR.

Limited company directors

A limited company is a separate legal entity, so it gets its own company UTR for Corporation Tax. Directors who receive dividend income or have other personal tax obligations will often need a personal UTR for their own Self Assessment filing too. The two are not interchangeable.

Partnerships

Partnerships carry the most complexity. The partnership itself needs a UTR to file the main partnership return, and each individual partner also needs their own personal UTR to report their share of profits. That can mean multiple UTRs in play for a single business structure.

PAYE employees with additional income

Most employees paid through PAYE won't need a UTR. But, you may need one if you have untaxed rental income, foreign income, capital gains, or an income level that pulls you into Self Assessment.

How does a UTR differ from other UK tax identifiers?

This is where founders and new business owners often get tripped up. Several identifiers arrive at once during the early stages of business formation, and they each do a different job.

One distinction worth emphasising: your CRN is public and appears on company filings and invoices. Your UTR is confidential and should never be shared openly or stored without care.

How to apply for a UTR number

For most people, the fastest route is online through the GOV.UK Self Assessment registration flow.

Option 1: Register online (the fastest route)

1. Create a Government Gateway user ID using your National Insurance number, home address, and date of birth.

2. Log in and navigate to the Self Assessment registration section.

3. Enter your business details and the date you started trading.

4. Submit the form. HMRC posts your UTR to your registered address within 10 to 15 working days.

Note that HMRC sends UTRs by post for security reasons. The number doesn't appear on screen immediately after submission.

Option 2: Limited company registration

If you've recently incorporated, you don't need to apply separately. Companies House notifies HMRC after incorporation, and HMRC automatically issues the company UTR and sends it to the registered office — typically within 14 days.

Option 3: Postal registration

Paper routes are available if you can't use online services. HMRC accepts Form SA1 for individuals with untaxed income and Form CWF1 for the self-employed. These routes are slower and can take several weeks to process.

The key deadline:You must register by 5 October following the end of the tax year in which you started trading. Miss that and you risk late-notification penalties and complications at filing time.

How to find your UTR number if you've lost it

If HMRC has already issued your UTR and you can't locate it, work through the digital options before calling.

Step 1: Check your Government Gateway account.Log into your HMRC Personal Tax Account or business dashboard. If it's active, your UTR is displayed in the account summary.

Step 2: Use the HMRC mobile app.Your UTR appears at the top of the account summary once you're logged in.

Step 3: Check previous HMRC correspondence.Your UTR is printed on your SA250 welcome letter, notices to file, payment reminders, and any previous tax return paperwork.

Step 4: Contact HMRC directly.Call the Self Assessment helpline on 0300 200 3310. But, HMRC won't read your UTR out over the phone. If you can't find it any other way, they'll post it to your registered address after verifying your identity — reliable, but not instant.

Why your UTR is confidential — and when you're expected to share it

Your UTR is tied directly to your tax identity. Mishandling it can increase the risk of tax fraud, identity theft, and unauthorised access to your filings or HMRC correspondence. Treat it with the same care you'd give your National Insurance number.

There are two situations where sharing your UTR is both expected and appropriate:

• With your accountant or tax adviser. If they're formally acting for you with HMRC, they'll need your UTR to access your tax record and file on your behalf.

• With a contractor under the Construction Industry Scheme (CIS). If you work as a subcontractor, the contractor needs your UTR to verify your details before making payments to you.

That second situation carries a direct financial consequence. A verified UTR means CIS deductions at the standard 20% rate. Without a valid UTR, HMRC can require the contractor to deduct 30% instead. On a £20,000 contract, that's an extra £2,000 withheld — a material difference in cash flow.

UTR number vs unique transaction reference: what's the difference?

There's one more source of confusion worth addressing — particularly for businesses involved in international payments.

In UK tax, UTR stands for Unique Taxpayer Reference. In banking — specifically for transfers using Indian payment rails such as NEFT, RTGS, or UPI — UTR can also stand for Unique Transaction Reference. These are completely different things.

If you've landed here looking for a reference number to trace a bank transfer, that's generated by your payment provider — not by HMRC.

Get the right financial infrastructure in place once your UTR is sorted

Getting your UTR is the compliance step. Choosing the right business account is the operational one.

Once you're registered, separating personal and business finances early makes a genuine difference. It keeps bookkeeping cleaner, simplifies reporting at filing time, and reduces friction when working with accountants. And, if you're trading internationally or managing payments in more than one currency, the right account can save you a meaningful amount on every transaction.

That's where traditional options often fall short. Many high-street banks and domestic-only digital accounts charge FX markups of 2.75–3% on international payments— costs that compound quickly once you're paying overseas suppliers or collecting revenue in foreign currencies.

The Airwallex digital business account is built for UK businesses that need multi-currency capability from day one:

• Global Accounts — hold and collect balances in 20+ currencies without forced conversion

• Borderless Cards — issue corporate cards with 0% international transaction fees and built-in spending limits

• Invoicing and billing — create, send, and reconcile invoices globally across 160+ payment methods

• Accounting integrations — sync directly with Xero or QuickBooks to automate reconciliation and keep records clean from the start

If you're weighing up alternatives, our Monzo business account review, Starling business account review, and Tide business account review break down how each compares on fees, features, and international capability.

Frequently asked questions

Is my UTR number on my payslip?

No. Payslips show your PAYE tax code and National Insurance number — not your UTR. You'll find your UTR in your Government Gateway account or on previous HMRC correspondence such as a notice to file or SA250 welcome letter.

Can I be self-employed without a UTR?

You can start trading before HMRC has issued your UTR, but you must register for Self Assessment by 5 October following the end of the tax year in which you became active. Operating past that deadline without registering can result in late-notification penalties.

Does everyone in the UK have a UTR?

No. UTRs are only issued to individuals and entities with specific tax obligations. If you're employed and have no additional income outside PAYE, you most likely don't have one.

Can my UTR be changed?

No. Once issued, a UTR stays permanently attached to that person or legal entity. It doesn't change if you move address, change your trading name, or stop trading for a period.

Sources and references

1. GOV.UK, “Find your UTR number” https://www.gov.uk/find-utr-number

2. GOV.UK, “Check how to register for Self Assessment” https://www.gov.uk/register-for-self-assessment

3. GOV.UK, “Self Assessment tax returns: Deadlines” https://www.gov.uk/self-assessment-tax-returns/deadlines

4. GOV.UK, “Self Assessment tax returns: Who must send a tax return” https://www.gov.uk/self-assessment-tax-returns/who-must-send-a-tax-return

5. GOV.UK, “Personal tax account: sign in or set up” https://www.gov.uk/personal-tax-account

6. GOV.UK, “Set up a private limited company: Register for Corporation Tax” https://www.gov.uk/limited-company-formation/set-up-your-company-for-corporation-tax

7. HM Revenue & Customs, “298,905 Self Assessment filers quick off the mark” https://www.gov.uk/government/news/298905-self-assessment-filers-quick-off-the-mark

8. LITRG, “Construction industry scheme (CIS)” https://www.litrg.org.uk/working/self-employment/construction-industry-scheme-cis

9. Monzo, “Business banking plans and pricing” https://monzo.com/business-banking/plans-pricing

10. Monzo, “International payments” https://monzo.com/business-banking/features/international-payments

11. Starling Bank, “Business account” https://www.starlingbank.com/business-account/

12. Starling Bank, “International payments country fees” https://www.starlingbank.com/send-money-abroad/country-fees/

13. Tide, “Pricing” https://www.tide.co/pricing/