Registering for Self Assessment – Step-by-Step Guide (2025 Edition)
Whether you’re newly self-employed, a landlord, or earning untaxed income, registering for Self Assessment is a crucial first step in managing your UK tax obligations.
This step-by-step guide walks you through how to register for Self Assessment in 2025, deadlines to watch, and tips to stay compliant.
Who Needs to Register for Self Assessment?
You must register if you:
- Are self-employed or a sole trader
- Earn more than £1000 from a side hustle
- Are a company director
- Receive rental income
- Have income from savings, investments, dividends or crypto assets
- Need to pay the High Income Child Benefit Charge
- Have capital gains to report
Key Deadlines for 2025
- 5 October 2025 – Deadline to register for Self Assessment if you need to file for the 2024/25 tax year
- 31 January 2026 – Deadline to file online tax return and pay any tax due for 2024/25
Step-by-Step: How to Register
Step 1: Create a Government Gateway Account
- Visit gov.uk
- Choose “Create sign in details”
- Provide your email, full name, and create a password
Step 2: Register for Self Assessment
- Log into your Government Gateway account
- Select “Register for Self Assessment”
- Choose the correct form based on your circumstances:
- Form CWF1: For the newly self-employed
- SA1: For those not self-employed (e.g., landlords or investors)
Step 3: Receive Your Unique Taxpayer Reference (UTR)
- HMRC will send your 10-digit UTR by post within 10 working days (21 days if abroad)
- You need your UTR to file your return and make payments
Step 4: Activate Your Online Account
- HMRC will send you an activation code
- Use it to access your online tax account and submit your return securely
After Registration: What Next?
- Start recording income and allowable expenses
- Keep receipts, invoices, and bank statements
- Use accounting software (like Xero, QuickBooks, or FreeAgent) to simplify tracking
Penalties for Late Registration or Filing
- £100 penalty if your return is up to 3 months late
- Daily penalties and interest apply for longer delays
Don’t risk missing deadlines. Early registration ensures you’re set up well in advance.
How Eclat Accountancy Can Help
At Eclat Accountancy, we assist:
- First-time Self Assessment filers
- Landlords, freelancers, and small business owners
- Clients with international income or crypto gains
We handle the registration process, ensure correct setup, and provide ongoing tax return support.
Final Thoughts
Registering for Self Assessment in 2025 doesn’t have to be stressful. With the right guidance and early action, you can stay on top of your tax responsibilities and avoid penalties.
Contact Eclat Accountancy today for help registering, filing, and managing your taxes with ease.
