What is the SA103 self-employment form?
The SA103 is the supplementary form where a sole trader reports business income and expenses on the SA100. It comes in a short version, SA103S, and a full version, SA103F. HMRC says the short one is for self-employed people with relatively simple tax affairs whose annual turnover was below the VAT threshold.
Figures checked against gov.uk on . General information, not tax advice.
Short or full
The SA103S has fewer boxes and suits straightforward trading: turnover, allowable expenses and the resulting profit. If your turnover was at or above the VAT threshold for the tax year, or your affairs are more complicated, you use the full version instead. The threshold amount changes, so check HMRC's current figure rather than relying on an old one.
What you enter
You report turnover and then deduct allowable expenses, or the trading allowance if that gives a better result. The difference is your taxable profit, which feeds the Income Tax and Class 4 National Insurance calculation on the main return.
Profit is taxed by tax year, not by accounting period, so a business with a year-end of, say, 31 December has its profit split across tax years.
- Allowable expenses and the trading allowance cannot both be used against the same income.
- If you use traditional accounting rather than the cash basis, you must say so on the return.