Tax Category Tax: calculations, VAT, self-employment tips and more

What is a tax reference number in the UK

Dealing with HMRC can be a fraught task for individuals and companies. The taxman can ask for lots of information and at times seems to quote various reference numbers on different forms and pieces of correspondence. Understanding tax reference numbers will help you avoid one potential headache when trying to sort your tax affairs.

National Insurance number

Your National Insurance number is not a tax reference number, but you will often be asked for it when dealing with some departments at HMRC or when contacting your HR department at work with tax queries. Your National Insurance number is your personal account number in relation to your National Insurance and tax contributions and ensures that everything you pay is recorded against your name. You should be given a number when you reach the age of 16 and the number should be made up of number and letters such as AB 12 34 45 C.

Tax reference number

A tax reference number is a number provided to each employer and pension provider to identify tax records with HMRC. The number will be made up of three numbers followed by several more numbers, letters or a combination of both. The reference number will identify your local tax office and your employer, and should appear on payslips, your form P60 which you should receive from your employer annually, and your P45 if you leave that particular employer.

Unique Taxpayer Reference (UTR)

A Unique Taxpayer Reference (UTR) is issued by HMRC when you are self-employed and register for self-assessment. Your UTR will be a 10-digit number and will be included on your tax return form (SA100), a notice to complete a tax return (SA316) and on the statement of account that you receive from HMRC. You will also need to use this number to log onto the self-assessment online system.

Corporation Tax reference number

A Corporation Tax payment reference number is required for making payments of Corporation Tax. This number will be quoted on the Corporation Tax online service, payslips and correspondence about this tax. The number will be 17 characters long consisting of numbers and letters. The HMRC’s website ( has a Corporation Tax reference checker where you can enter the number and check that you have it in the right format.