Registering for Self Assessment

Who needs to register

Register for Self Assessment if you:

• Started trading as a sole trader
• Started letting out property (more than the £1,000 property allowance)
• Became a partner in a partnership
• Earn over £150,000 from PAYE alone (no longer required from 2024-25 — check current rules)
• Have other untaxed income that requires reporting (dividends, foreign income, capital gains)

The deadline

Register by 5 October following the end of the tax year in which you became liable. So if you started trading in the 2024/25 tax year, register by 5 October 2025.

Late registration can trigger a "failure to notify" penalty based on the tax owed. Better to register early and be safe.

How to register

1. Sign in to your Government Gateway, or create one if you don't already have it
2. Use HMRC's online registration service for Self Assessment
3. Provide details of your business or trading activity
4. Wait for HMRC to issue your UTR (Unique Taxpayer Reference) — comes by post in 7-10 working days
5. You'll then receive an activation code for the Self Assessment online service

What happens after registration

• You're now in the Self Assessment system — file a tax return every year
• Class 2 NI is collected automatically through Self Assessment for self-employed
• If profits exceed £6,725 (2024/25), you'll also pay Class 4 NI
• You can deregister later if you stop trading