An individual or partnership registering for self-assessment with HMRC is issued with A Unique Tax Reference (UTR) number. This is a 10 digit number which is sometimes shown with a ‘K’ as a suffix. The UTR number is included on the registration letter which HMRC send out, as well as on any future correspondence.
Similarly, when a limited company is incorporated (formed), HMRC automatically assign a UTR number to it. A company’s UTR number begins with 3 numbers (which relate to the assigned CT office), a 10 digit reference number and the letter ‘A’. For example, 123 45678 91011 A
If at any time you misplace your UTR number and do not have any correspondence from HMRC with the number on, then you can contact HMRC, and they will post a reminder to the address you have registered with them.
Employer’s reference number and accounts office reference number
When a business registers as an employer with HMRC, they are issued with an employer’s reference number and an accounts office reference number. These are shown on the confirmation of registration letter sent out by HMRC.
The first 3 digits of the employer’s reference number relate to the PAYE office looking after your account. The remaining digits are a unique reference.
The accounts office reference number is made up of 13 characters, presented in the following format; 123PA12345678. You can use the online HMRC checker to verify this number.
You can contact the HMRC employer helpline to request these reference numbers again if you misplace them.