How to Apply for UTR Number Online or by Post: Full HMRC UK Self Assessment Guide

Applying for a UTR number means registering with HMRC for Self Assessment online, by post, or via the separate route for people who are not self employed, so HMRC can issue the ten digit Unique Taxpayer Reference needed to file returns. As of August 2026, registration is free and typically takes fifteen days.

Key takeaways

• HMRC issues a UTR number free of charge to anyone who registers for Self Assessment, whether online, by post, or through the separate route for people who are not self employed.
• The ten digit Unique Taxpayer Reference usually arrives by post within fifteen days of registration, per GOV.UK guidance updated in August 2026.
• People who are not self employed still need a UTR for rental income, foreign income, or the High Income Child Benefit Charge, using form SA1 rather than the self employed route.

How to Apply for UTR Number Online?

Register for Self Assessment online through GOV.UK for the fastest route to a UTR number. Registering online is free, and most applicants complete the process in under fifteen minutes once the details are ready.

The online application runs through six stages:

1. Visit the official Self Assessment registration service on GOV.UK and select the option matching personal circumstances
2. Create a Government Gateway account using an email address, or sign in if one already exists
3. Enter full name, date of birth, home address, and National Insurance number
4. Provide details of the reason for registering, including a business start date if self employed
5. Submit the application and note any confirmation reference shown on screen
6. Wait for the UTR to arrive by post, or check a personal tax account once it has been issued

Keep the Government Gateway login details safe, since the same account gives access to a personal tax account, the HMRC app, and future Self Assessment filing.

How to Apply for UTR Number by Post?

Apply by post using form SA1 or CWF1 when the online service cannot be used, though this route generally takes longer. Choose the form that matches the reason for registering rather than defaulting to the self employed option.

A few checks matter before the form goes in the post:

• Use form CWF1 for self employment or sole trader registration
• Use form SA1 for any other reason, such as property income or the High Income Child Benefit Charge
• Use form SA400 if registering a business partnership rather than an individual
• Print the completed form and check every field before sending it
• Post the form using a trackable delivery service where possible, since a postal application cannot be saved and resent online

Postal applications are processed on working days only, so a form posted before a bank holiday weekend may take slightly longer to arrive. Anyone with a filing deadline only weeks away should register online instead wherever possible.

Can You Apply for a UTR Number by Phone?

GOV.UK’s own Self Assessment registration service offers only the online route, alongside form SA1 or CWF1 by post. Phone registration is not listed as an independent method on HMRC’s official service page.

The Self Assessment helpline supports people who need help completing an application or who have lost an existing UTR, rather than acting as a standalone registration channel.

Anyone planning to call should check the current HMRC Self Assessment contact number and opening hours first, since these change occasionally. An advisor can talk someone through the process, but registration itself still happens through the online service or the relevant postal form.

Some informal guides describe calling HMRC as a full alternative to registering online, which overstates what the helpline does. HMRC’s own GOV.UK page backs this up, listing the helpline as support rather than as a way to register.

Who Needs to Apply for a UTR Number?

Anyone required to file a Self Assessment tax return needs to apply for a UTR number, since HMRC uses this reference to identify every taxpayer’s record. The requirement extends well beyond people who describe themselves as self employed.

Overseas equivalents are sometimes called a tax identification number, but the UTR itself is an HMRC specific reference used only within the UK tax system.

HMRC expects a UTR from:

• Sole traders and self employed individuals earning over 1,000 pounds a year before expenses
• Partners in a business partnership
• Landlords receiving rental income above the tax free threshold
• Company directors filing a personal Self Assessment return alongside company accounts
• Construction workers registered under the Construction Industry Scheme, known as CIS

A UTR stays with a person for life once issued, so most individuals only apply once. Many sole traders use this stage to review pension provision as well, since a self employed pension plan is arranged privately rather than through a PAYE workplace scheme.

Confirm Your Registration Route Before You Apply

Not everyone who needs a UTR is self employed, and HMRC splits registration into two routes depending on the reason. Picking the wrong route at this stage is one of the easiest mistakes to make, and it usually adds weeks to the process.

People register through form SA1, rather than the self employed route, when they:

• Receive income from land or property in the UK
• Have taxable foreign income
• Need to pay the High Income Child Benefit Charge and have not chosen to pay it through PAYE
• Receive yearly income from a trust or settlement
• Receive untaxed income that HMRC cannot collect through a PAYE tax code
• Have Capital Gains Tax to pay

HMRC separates the two routes because self employment registration also sets up Class 2 National Insurance treatment, which does not apply to rental or investment income alone. Using the wrong form can create an incorrect National Insurance record that takes months to correct.

A person who owes the High Income Child Benefit Charge but has never been self employed must still register using form SA1, and missing the 5 October deadline can still trigger a penalty, even though no business is involved.

How Long It Takes, What It Costs, and What to Do If Time Is Short?

Whether applying for a UTR number online or by post, HMRC charges no registration fee. Most postal deliveries reach UK addresses around fifteen days after registration, a figure confirmed as of August 2026 via GOV.UK.

Anyone with a filing deadline only weeks away should register as early as possible, since HMRC cannot issue a UTR any faster on request.

Paying a third party agent rarely speeds up HMRC’s own processing, since the agent submits the same application into the same system. The real advantage of an agent is having someone check the form for errors, not a guaranteed faster UTR.

Getting a UTR Number for a Limited Company

Getting the Company UTR

Companies House automatically notifies HMRC when a company is incorporated, and HMRC issues a company UTR without a separate application. It usually arrives within around 14 days, sent to the registered office address held by Companies House.

This UTR is used exclusively for Corporation Tax and should not be confused with a director’s personal UTR.

The Director’s Personal UTR

A company director still needs a personal UTR when filing a personal Self Assessment return, which most directors do. This personal UTR is entirely separate from the company’s reference and must be applied for individually through the routes described above.

Directors juggling company profits, salary, and dividends often need to work out personal tax due on top of Corporation Tax already paid by the company.

Since dividend income is taxed separately from salary, running the numbers through a dividend tax calculator before the Self Assessment deadline can make that split easier to plan for.

Common Myths About Applying for a UTR Number

A handful of misconceptions about UTR numbers keep resurfacing among first time applicants, and most lead to either wasted time or wasted money.

Common myth	What is actually true
Only self employed people need a UTR	Landlords, company directors, and anyone with certain untaxed income also need one, often through form SA1
Applying for a UTR number costs money	HMRC issues a UTR free of charge, whether applying online or by post
A UTR can be obtained instantly by phone	The Self Assessment helpline supports applications but is not itself a registration channel
A limited company must apply for its own UTR	Incorporation with Companies House automatically triggers HMRC to issue a company UTR
A lost UTR means starting registration again	An existing UTR can usually be found on a personal tax account, the HMRC app, or previous HMRC letters
Every household member shares the same UTR	Each individual and each company holds its own separate ten digit reference

What to Do After You Receive Your UTR Number?

Set up online access to a personal tax account once a UTR number arrives, since this becomes the main tool for managing Self Assessment. Sorting out a handful of things in the weeks that follow makes the run up to the filing deadline far less stressful.

1. Activate the online Self Assessment account using the activation code sent alongside or shortly after the UTR
2. Save the UTR somewhere secure, since it will be needed for every future tax return and payment
3. Note the 31 January online filing deadline and the 31 July second payment on account date, where relevant
4. Register for Making Tax Digital if turnover exceeds the applicable threshold once it becomes mandatory in phases from April 2026
5. Look into allowable expenses early on, such as working from home tax relief for anyone splitting time between home and client work

Keeping records from the start of the tax year makes the first Self Assessment return far less stressful than gathering everything in January.

Conclusion

Knowing how to apply for a UTR number comes down to choosing the correct route, whether that means registering online, by post, or through form SA1 for those who are not self employed. Getting this right the first time avoids delays and satisfies HMRC’s filing deadlines.

Applying for a UTR number, done through the right route, means straightforward, free registration with HMRC for anyone in the UK in 2026.

FAQ

Is Self Employment Required to Apply for a UTR Number?

No. Anyone with rental income, foreign income, trust income, or a High Income Child Benefit Charge liability needs a UTR through form SA1, regardless of employment status.

How Much Does a UTR Number Cost?

No cost applies when registering directly through HMRC online or by post. Some third party agents charge a fee, typically £20 to £30, for handling the application.

Is Phone Registration Available for a UTR Number?

No, not as a standalone method. The Self Assessment helpline offers support, but registration happens through the online service or a postal form.

How to Register as Self Employed for the First Time?

Register through the online Self Assessment service and select the self employed option, or post a completed form CWF1 if online cannot be used. HMRC then issues the UTR by post within around fifteen days.

How to Find an Existing UTR Number?

Check a personal tax account, the HMRC app, or previous Self Assessment correspondence such as a notice to file or a payment reminder. The number appears near the top of most official HMRC letters.

Disclaimer: This guide is for informational purposes only; consult HMRC or a qualified tax professional for official advice.