First Self Assessment? Everything you need to know

Your first tax return feels daunting, but most of the work is getting set up properly. Do these things in order and January won't be a shock.

Do you need to register?

You usually need to file a return if you were self-employed and earned more than £1,000 from it in the tax year. Other common reasons are rental income over £1,000, or other untaxed income over £2,500.

Register by 5 October

Register for Self Assessment by 5 October after the end of the tax year you started. If you started in, say, June 2025 (the 2025/26 tax year), register by 5 October 2026. HMRC then posts your UTR. This can take a couple of weeks, so don't leave it late.

Keep simple records from day one

You don't need accounting software for a first return. You do need:

• A record of every payment you receive, with the date and who paid
• A record of every business expense, with receipts kept for five years after the 31 January deadline
• Ideally, a separate bank account for business money

The January surprise

In your first year, if your bill is over £1,000, HMRC usually asks for the full bill plus 50% of it in advance towards next year. That's called a payment on account. On a £3,000 bill, that's £4,500 due on 31 January, then another £1,500 on 31 July.

This catches out more new freelancers than anything else. Our guide on how much to set aside explains how to plan for it.

Your first-year checklist

• Register and get your UTR
• Set aside 20–30% of what you earn in a separate savings account
• Track income and expenses monthly, not once a year
• Check whether Making Tax Digital applies to you
• File online before 31 January

General guidance, not tax advice.