Self assessment · Registration guide · UK
How to register for self-assessment UK: step-by-step guide.
Source: gov.uk/register-for-self-assessment. [VERIFY all deadlines before acting.]
Who needs to register?
You must register for self-assessment if you have untaxed income that HMRC has not collected via PAYE. This includes rental income above £1,000, self-employment income above £1,000, dividends above the dividend allowance for higher-rate taxpayers, income above £100,000, and company director income. The registration deadline is 5 October following the tax year in which the income arose. [VERIFY current criteria at gov.uk]
How to register — step by step
Check if you need to register
Review HMRC's criteria. If you received rental income, self-employment income, dividends not covered by your allowance, or director income in the tax year — you likely need to register. [VERIFY current criteria at gov.uk]
Register by 5 October
The deadline is 5 October following the tax year end. For 2025/26 income: register by 5 October 2026. Earlier is better — UTR delivery takes time.
Go to gov.uk/register-for-self-assessment
Choose the right registration route: self-employed, landlord/rental income, director, or 'other income'. You will need your National Insurance number and contact details.
Create a Government Gateway ID
You will need a Government Gateway user ID and password. If you don't have one, create it during registration. Keep the details — you'll need them to file and to authorise your accountant.
Wait for your UTR by post
HMRC sends your 10-digit Unique Taxpayer Reference (UTR) by post. Allow 10 working days. This number is needed to file your return and authorise your accountant.
Set up the HMRC app or online account
Once you have your UTR, set up your HMRC online account to manage self-assessment, view statements, and make payments. Or provide the UTR to your accountant so they can act on your behalf.
FAQs
Who needs to register for self-assessment?
You must register for self-assessment if in the previous tax year you: earned income from property rental; were self-employed with income above £1,000; earned income not taxed at source above £2,500; received dividends and are a higher or additional-rate taxpayer; had income above £100,000; were a company director; or received any other untaxed income. If HMRC has sent you a notice to file, you must file even if you believe you don't need to. [VERIFY current criteria at gov.uk/self-assessment-tax-returns]
When is the deadline to register for self-assessment?
If you need to register for the first time, the deadline is 5 October following the end of the tax year in which the income arose. For 2025/26 income (which started 6 April 2025): register by 5 October 2026. Missing this deadline can result in a late registration penalty. [VERIFY at gov.uk]
What is a UTR number?
A UTR (Unique Taxpayer Reference) is a 10-digit reference number that HMRC issues when you register for self-assessment. Every registered taxpayer has one. You need your UTR to file your return, set up a HMRC online account, and authorise an accountant to act on your behalf. HMRC sends it by post — it typically takes 10 working days after registration.
How do I register for self-assessment online?
Register via HMRC's Government Gateway at gov.uk/register-for-self-assessment. You will need: your National Insurance number; personal contact details; details of your income sources; and a Government Gateway user ID (or to create one). Different registration routes exist for self-employed, landlords, and directors. [VERIFY: current registration process at gov.uk/register-for-self-assessment]
How long does it take to register?
Online registration takes around 10–15 minutes. HMRC then sends your UTR by post — typically within 10 working days. Allow extra time around the October deadline period when volumes are high. Do not leave registration until October if you need the UTR to authorise an accountant or set up digital services — start earlier.
Do landlords need to register for self-assessment?
Yes — if your rental income exceeds £1,000 per year, you must register for self-assessment and declare it. Even if your profit after expenses is below the personal allowance, you must still file if your gross rental income exceeds the threshold. MTD for Income Tax adds a further obligation from April 2026 for landlords above £50,000 gross. [VERIFY current thresholds at gov.uk]
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