First-time Self Assessment: the checklist

First returns generate more panic per pound of tax than any other filing — mostly because the process is unfamiliar, not because it's hard. Here's the sequence.

Step 1 — Register (by 5 October)

Register for Self Assessment on GOV.UK as soon as you know you need to file — newly self-employed, new landlord, high earner asked to file, or side income over £1,000. HMRC posts your UTR (Unique Taxpayer Reference) within about two weeks. Nothing else can happen without it, so don't leave this for January.

Step 2 — Gather the year

• Income: invoices or platform statements for self-employment; P60/P45 and P11D if also employed; rental statements; dividend vouchers; bank interest summaries
• Expenses: receipts, mileage log, home-office basis — see our expenses guide
• Anything HMRC sent you: coding notices, letters, previous statements
• Student loan plan type and pension contributions — both change the calculation

Step 3 — Understand what you'll pay

Income tax on profits above the personal allowance, plus Class 4 National Insurance. First-year filers are regularly ambushed by payments on account: if your bill tops £1,000, HMRC asks for 150% of it by 31 January (this year's bill plus half of next year's in advance). Knowing this in October beats discovering it in January.

Step 4 — File and pay by 31 January

The return itself is a long form asking about every income type; only the sections relevant to you need completing. File online, check the calculation it produces, pay by 31 January. Then set up a separate savings pot and move 25–30% of profit into it monthly — future you, next January, will be genuinely grateful.

Or hand the whole sequence to us: £129 fixed, including registration guidance, the return, the supplementary pages and the payments-on-account explanation in plain English.