How to register, step by step
- Check that you need to register. You must register if you were self employed and earned more than £1,000, received rental income, had untaxed income such as dividends above your allowance, or need to report the High Income Child Benefit Charge.
- Choose the right route. If you are self employed you register for Self Assessment and Class 2 National Insurance together. If you are not self employed, for example a landlord, you register using form SA1 instead.
- Register online with HMRC. Complete the online registration with your name, address, National Insurance number and the date you started. HMRC sets up your Self Assessment record.
- Wait for your UTR. HMRC posts your 10 digit UTR within about 10 working days. You cannot file without it, so do not leave registration to the last minute.
- Activate your online account. A separate activation code arrives by post. Enter it in your Government Gateway account to unlock online filing, then you are ready to complete the return.
Common mistakes
- Leaving it too late. The UTR and activation code both come by post, so registering in January is cutting it dangerously fine.
- Using the wrong route. Registering as self employed when you are only a landlord, or the other way round, causes delays.
- Assuming small income means no registration. If you cross £1,000 of trading income, or HMRC asks you to file, you must register.
Not sure if you need to register?
If you are unsure whether you need to register, or which route applies, TaxTune checks your position, registers you correctly and takes the return off your hands, all on a fixed fee agreed up front.
Let us get you registered and filed
Send us your details and we will register you with HMRC, get your UTR sorted, and prepare and file your return on time. No jargon, no missed deadlines.
Frequently asked questions
When do I need to register for Self Assessment?
By 5 October following the end of the tax year in which you started being self employed, receiving rental income or earning other untaxed income. For example, if you started in the 2025/26 tax year, register by 5 October 2026.
What is a UTR?
A Unique Taxpayer Reference is the 10 digit number HMRC uses to identify you for Self Assessment. You receive it by post after registering and need it to file your return and pay your tax.
What if I miss the 5 October deadline?
Register as soon as you can. As long as you still file and pay by 31 January, you may avoid a penalty, but late registration risks missing the filing deadline because the UTR arrives by post.
Do I need to register if I earn under £1,000?
The £1,000 trading allowance means you may not need to register or pay tax on small amounts of trading income. If you cross £1,000, or HMRC asks you to file, you must register.
How long does registration take?
Expect about 10 working days for your UTR to arrive by post, then a little longer for the activation code. Allow two to three weeks before you can file online.