Guide to Tax Identification Numbers (TINs) in the UK

Tax identification numbers, commonly known as ‘TIN numbers’ or simply ‘TINs’, are used for official purposes in managing various types of taxation. They help to identify taxpayers and facilitate the administration of their tax affairs across all jurisdictions.

In this blog post, we explain everything you need to know about the different types of TIN numbers applicable to individuals and business entities in the UK, including what they are used for and how to obtain them.

This information will be helpful to you when running a business as a self-employed person or the director and shareholder of a limited company.  

What is a tax identification number (TIN)?

A tax identification number is a unique number (or a combination of letters and numbers) used to identify a particular individual or entity for tax administration purposes. It is generally the most useful piece of data for tax authorities to correctly match or link a taxpayer’s reported information with the details they hold about them. 

However, it’s important to mention that the UK does not issue anything officially known as a ‘Tax Identification Number’. It’s more of a generic umbrella term for various types of identification numbers and references relating to personal and business taxation. In the UK, these include: 

1. Unique Taxpayer Reference (UTR)
2. National Insurance number (NINo)
3. Company registration number (CRN)
4. VAT registration number 
5. Employer PAYE reference

HM Revenue & Customs (HMRC), the UK tax authority, is responsible for issuing TIN numbers in the UK. The only exception is company registration numbers. CRNs are issued by Companies House – the UK Registrar of Companies.

The names and format of TINs differ from country to country. Sometimes they comprise only numbers, but many also include letters. Outside the UK, TINs may include social security numbers, citizen or personal identification codes, and resident registration numbers.

The terms ‘Tax Identification Number’ and ‘TIN’ are not commonly used in the UK in any official capacity. However, when dealing with foreign businesses or tax authorities – particularly in America and the EU – you may encounter specific references to them. Sometimes UK companies may be asked to provide a tax identification number to be able to carry out business abroad.

This post focuses solely on TINs in the UK. Below, you will find a detailed overview of the different types of tax identification numbers you may encounter as an individual taxpayer or business owner in the UK.

1. Unique Taxpayer Reference (UTR)

A Unique Taxpayer Reference is a 10-digit number that HMRC assigns to companies, business partnerships, and certain individuals who file personal tax returns. It is often simply referred to as a ‘tax reference’ or ‘UTR’. 

Company and partnership UTRs

HMRC automatically issues a company Unique Taxpayer Reference, or ‘Corporation Tax Unique Taxpayer Reference’, to all companies when they incorporate at Companies House.

When running a limited company, you will need to provide this particular TIN number on many occasions, such as when:

• registering for Corporation Tax
• filing Company Tax Returns and annual accounts with HMRC 
• paying your Corporation Tax bill 
• registering for Value Added Tax (VAT)
• registering for Pay As You Earn (PAYE)
• updating certain business details with HMRC 
• changing your Corporation Tax accounting period
• making the company dormant for Corporation Tax 
• corresponding with HMRC about anything else relating to your company’s tax affairs

For limited liability partnerships (LLPs) and limited partnerships (LPs), HMRC automatically issues a partnership UTR upon their incorporation at Companies House. Ordinary (traditional) partnerships receive a partnership UTR when they register for Self Assessment with HMRC.

You will need to provide this particular tax identification number for your partnership when:

• registering an LLP or LP for Self Assessment 
• filing an annual Partnership Tax Return through Self Assessment
• registering for VAT and PAYE
• notifying HMRC of certain changes to the partnership 
• contacting HMRC about anything else relating to the partnership’s tax affairs 

HMRC will send a letter containing your company or partnership UTR to your registered office or business address. You should receive this TIN number within 15 days of incorporating at Companies House or registering for Self Assessment.

Where to find the UTR for your company or partnership

You can find your company or partnership UTR by logging in to your HMRC online business tax account or using the HMRC app. You’ll also find this tax ID number on previous tax returns and official correspondence sent from HMRC, such as notices to file a tax return and payment reminders.

• How to register for tax after forming a company
• An introduction to Corporation Tax
• Do I need to file a Company Tax Return?

If you can’t find it anywhere, you may be able to request a copy of your company UTR online. To do so, you must provide your company registration number and registered company name. Once you have successfully requested it, a copy of this TIN will be sent by post to your registered office address.

However, you can’t request a copy of your company UTR if it has:

• been officially closed or dissolved
• been ‘struck off’ and no longer appears on the public register at Companies House
• changed to a different business structure, such as a partnership, and is no longer a registered company
• recently incorporated – the UTR should arrive at your registered address within 3 weeks of incorporation

If you’ve lost your partnership UTR, you need to contact HMRC’s Self Assessment department. 

Personal UTRs

HMRC issues personal Unique Taxpayer References to individual taxpayers who register for Self Assessment, including:

• sole traders and freelancers
• partners in a business partnership, including members of limited liability partnerships 
• anyone who has a total taxable income of more than £150,000 in a tax year
• company directors and shareholders
• Individuals who need to report and pay Capital Gains Tax on the sale or disposal of assets 
• anyone who has to pay the High Income Child Benefit Charge
• individuals who receive money from renting out a property, income from savings, investments, foreign income, or tips and commission

Self Assessment is the system that HMRC uses to collect tax on personal income that isn’t processed and taxed through payroll.

When you send a Self Assessment tax return, you need to provide your personal UTR, which serves as a type of TIN number. HMRC can then correctly identify you and link your filings and any payments you make to your official tax record. 

Where to find your personal Unique Taxpayer Reference

After registering for Self Assessment, you can find your personal UTR by signing in to your personal tax account or using the HMRC app. You need a Government Gateway user ID and password to create or access your HMRC online account.

• Do I need to register for Self Assessment if I run a Ltd company?
• Self Assessment for non-resident UK company owners
• How to register for Self Assessment

You’ll also find your personal Unique Taxpayer Reference on previous Self Assessment tax returns and official letters from HMRC, such as notices to file a tax return and payment reminders.

If you can’t find your UTR anywhere, you need to contact HMRC’s Self Assessment department to request a copy.

The difference between a TIN number and a Unique Taxpayer Reference

In the UK, a Unique Taxpayer Reference is simply one of several types of tax-related reference numbers that may be informally categorised as a ‘Tax Identification Number’ or ‘TIN’. However, UTRs are not officially referred to as TIN numbers in UK legislation or HMRC guidance.

2. National Insurance number

A National Insurance number (NINo) is a unique, personal TIN number that links individuals in the UK with their tax records. It relates to personal National Insurance contributions, tax payments, state benefits (including the State Pension), tax credits, and student loans. 

This tax identification number comprises a prefix of 2 letters followed by 6 numbers and a final letter suffix. NINos are usually provided to UK residents automatically, shortly before their 16th birthday.

National Insurance numbers are used by a variety of organisations for official tax purposes, including:

• HM Revenue and Customs
• employers – to use in their payroll systems
• Department for Work and Pensions – if someone claims state benefits
• local councils – in respect of any claims for Housing Benefit
• Electoral Registration Office – to check the identity of an individual when they register to vote
• Student Loan Company – in respect of any student loans
• pension providers – in respect of personal or stakeholder pensions
• Individual Savings Account (ISA) providers
• financial service providers – those authorised to help buy and sell investments like shares, bonds, and derivatives

You’ll need a National Insurance number if you live in the UK, have the right to work in the UK, and are currently working or planning to start working here. However, you can start work without a NINo, as long as you can prove your right to work in the UK. 

How to get a National Insurance number

HMRC automatically issues National Insurance numbers to UK residents in the 3 months before their 16th birthday if they:

• live in the UK, and 
• a parent or guardian completed a Child Benefit claim form for them 

You will receive your NINo by post at the address HMRC has for you. However, if you’re between the ages of 16 and 19 and haven’t received one, you can get your National Insurance number by:

• contacting HMRC’s National Insurance department – if your parent or guardian filled in a Child Benefit claim form for you
• applying online for a National Insurance number – if your parent or guardian did not fill in a Child Benefit claim form for you 

It’s worth checking with HMRC first because you may already have a National Insurance number. You keep the same NINo for life, so it’s not the type of TIN that HMRC will replace.  

If you have a biometric residence permit (BRP)

If you have a biometric residence permit, you may already have an NINo. If one has been issued, it will be shown on the back of your BRP. If you don’t have one, you need to apply for a NINo when you are in the UK and planning to work.

How to apply for a National Insurance number 

You can apply online for a National Insurance number if you live in the UK, have the right to work here, and can provide one of the following documents:

• a passport from any country
• a biometric residence permit (BRP)
• a national identity card from an EU country or from Norway, Liechtenstein or Switzerland

You can still apply for a NINo if you do not have any of these documents. However, you may have to attend an appointment in person to prove your identity and right to work in the UK.

Where to find your National Insurance number

There are various places you can look to find your National Insurance number, such as:

• payslips from employers 
• on a P60 form 
• any official correspondence from HMRC relating to your personal tax, pensions, or benefit payments
• your personal online account (i.e. if you’re registered for Self Assessment)

If you can’t find it anywhere, you can retrieve your National Insurance number online. Alternatively, you can fill in form CA5403 and send it to HMRC at the address on the form, or contact HMRC.

The difference between a TIN number and a National Insurance number

In the UK, a National Insurance number is a type of tax-related identification number that may be informally described as a TIN number. However, NINos are not officially referred to as ‘Tax Identification Numbers’ or ‘TINs’ in UK legislation or HMRC guidance.

3. Company registration number

The company registration number (CRN) is a combination of 8 characters (either 8 numbers, or 2 letters followed by 6 numbers). It is used to verify the legal existence of a company (or LLP) and identify it for all official purposes. Companies House assigns a unique CRN to every new company upon its incorporation. 

• How to register a company in 4 simple steps with 1st Formations

Whilst CRNs are not issued for taxation purposes, they are key to managing the tax affairs of companies. This TIN-like number enables HMRC (and foreign tax authorities, where applicable) to easily match and link various taxation records relating to a company and facilitate cross-referencing of data between government agencies. 

When will I need to use my company registration number?

Throughout the life of your company, you will need to provide your company registration in various situations. The most common of these are as follows, some of which relate to tax:

• Filing an annual confirmation statement with Companies House
• Submitting annual accounts to Companies House and HMRC
• Registering for Corporation Tax 
• Filing a Company Tax Return or Partnership Tax Return
• Paying your Corporation Tax bill 
• Registering for VAT and PAYE
• Filing VAT Returns and PAYE reports 
• Updating company details with Companies House, including a change of registered office address or change of company/LLP name
• Filing a Return of Allotment of Shares
• Issuing share certificates
• Appointing and removing company directors and secretaries 
• Opening business bank accounts in the company name 
• Applying for business loans or credit 
• Setting up accounts with suppliers
• Ordering or creating business stationery – by law, you must display your CRN on all official company stationery, including letterheads, invoices, websites, emails, and promotional materials

When dealing with HMRC for Corporation Tax matters, it will often be necessary to quote your company registration number and company Unique Taxpayer Reference.

How to get a company registration number 

You can only get a CRN by incorporating a company (or an LLP) at Companies House. You’ll receive your unique CRN as soon as Companies House approves and processes your registration application. It will appear on the certificate of incorporation, which you will receive by email. 

Where to find your company registration number

You’ll find your CRN on your certificate of incorporation and all official correspondence from Companies House. You can also view it in the public register of companies, which is free to access and search online. 

If you set up your company through 1st Formations, you can log in to your account in our Online Company Manager. There, you will find a host of information about your company, including the registration number.

If you’re not an existing customer of 1st Formations, you can create a free account with us and import your company details.

4. VAT registration number 

A VAT registration number is a type of TIN number that HMRC assigns to a business when it registers for Value Added Tax (VAT). You must register for VAT in the UK if your VAT-taxable turnover exceeds £90,000. Otherwise, registration is available on a voluntary basis.  

• Pros and cons of voluntary VAT registration
• VAT registration for UK companies with non-resident directors
• How to submit a VAT Return

VAT numbers in England, Scotland, and Wales usually start with the letters ‘GB’, followed by a series of 9 numbers. For example, ‘GB 123456789’. However, if your business is registered in Northern Ireland and you trade to the EU, your VAT number might begin with the letters “XI” instead of GB – for example, XI 123456789.

You must display your VAT number on all invoices you raise. You’ll also need to provide this TIN number when sending a VAT Return to HMRC, paying your VAT bill, applying for a VAT refund, and dealing with certain suppliers. 

How to get a VAT registration number 

To get a VAT number, you need to register for VAT with HMRC. After completing the registration process, HMRC will send you a VAT registration certificate by post, which will contain your unique VAT number. 

Where to find your VAT number 

You can find your VAT number by checking your VAT registration certificate, previous VAT Returns, copies of invoices you’ve raised, your accounting software, VAT notices from HMRC, or by signing in to your VAT online account. If you still can’t find it, you’ll need to contact HMRC. 

5. Employer PAYE reference

The final type of tax identification number to be aware of in the UK is the employer PAYE reference. It’s sometimes referred to as an ‘Employer Reference Number’ or ‘PAYE reference’.

You will receive an employer PAYE reference from HMRC if you register as an employer. It is a unique alphanumeric number that appears in the following format: a 3-digit tax office number, a forward slash, and a tax office employer reference. It will look something like this: 123/AB456.

If you’re an employer, you will need to provide your PAYE reference when setting up your payroll, paying wages, issuing payslips and P60s, sending PAYE reports to HMRC, and paying your PAYE bill.

Where to find your employer PAYE reference

You can find your employer PAYE reference in HMRC correspondence relating to your registration as an employer. You’ll also find it in your payroll software, on previous PAYE filings you have sent to HMRC, and on any payslips and P60s you’ve issued to employees. If you can’t find it anywhere, contact HMRC’s Employer Helpline on 0300 200 3200.

Thanks for reading

Although the terms ‘Tax Identification Number’ and ‘TIN number’ are not used in any official capacity in the UK, there are several tax-related ID reference numbers that may be informally described as such. The two most common are Unique Taxpayer References and National Insurance numbers.

It’s important to be aware of the different types of TINs you may encounter as an individual taxpayer or business owner in the UK. Hopefully, you now have a better understanding of what they are, the crucial roles they play in taxation administration, and where to find them.