First-Time Self Assessment: register & records checklist
Everything a first-time sole trader or landlord needs to register by 5 October and get records ready for January
Instant PDF download (8 pages). Print it or use it on your phone or tablet.
A plain-English, step-by-step checklist for anyone filing Self Assessment for the first time as a sole trader, side-hustler or landlord — covering the 5 October registration deadline, exactly how to register, and full record-keeping lists so January's tax return is straightforward rather than stressful.
What's inside
- Step-by-step registration routes for sole traders, landlords, and people who are both
- A plain-English explanation of the 5 October deadline and why leaving it late is riskier than it looks
- Full record-keeping checklists split by income type — self-employment, side hustles and rental property
- A realistic timeline from registering today through to the 31 January filing and payment deadline
- A list of the mistakes that trip up first-time filers most often, so you can avoid them
- Writable prompts to help you set up a record-keeping system you'll actually stick to
Questions
Probably not — you likely already have a UTR. Check old HMRC letters or your Personal Tax Account before applying, as registering again can create a duplicate record and cause delays. If you can't find your old UTR, contact HMRC to retrieve it rather than reapplying.
You can still register and file — it isn't the end of the world — but late registration is treated as a 'failure to notify' and can carry a penalty based on any tax owed, on top of the separate penalty for filing your return late. Register as soon as you realise, even if it's after the date.
Not necessarily. Many first-time sole traders and landlords with straightforward finances file their own return using HMRC's online service, especially if records have been kept consistently through the year. An accountant becomes more useful if your situation involves multiple income types, property sales, or you simply want peace of mind.
If that's your only additional income and it's under the £1,000 trading allowance threshold, you generally don't need to register or file for that income alone. Do still check whether any other income (rental, dividends, savings interest above your allowance) pushes you into needing to register regardless.
Broadly, anything wholly and exclusively for the business — materials, tools, software, a proportion of home costs if you work from home, and business mileage. Keep every receipt and a note of what it was for; this checklist's records section tells you exactly what to capture as you go.