SA103 self-employment pages: short (SA103S) or full (SA103F)?

Who needs it

• Sole traders who must file a Self Assessment return, including anyone whose self-employed income was over the £1,000 trading allowance.
• SA103S: self-employed people with relatively simple affairs and turnover below the VAT registration threshold.
• SA103F: self-employed people whose turnover was above the VAT registration threshold, or whose affairs are more complex.
• Partners don't use SA103. Their share of profits goes on the partnership pages (SA104).

What you need before you start

• Your total business income (turnover) for the period.
• Your allowable business expenses, by category, or the flat rates if you use simplified expenses.
• Mileage records if you claim the simplified vehicle rate.
• Details of any equipment bought, for capital allowances.
• Your accounting dates, if you don't use the tax year (6 April to 5 April).

How to file SA103

1. 1Check your turnover against the VAT registration threshold to see whether the short page is open to you.
2. 2Total your income and expenses from your records. Since the 2024/25 tax year the cash basis is the default, so you record money when it comes in and goes out unless you opt out.
3. 3Decide whether flat-rate simplified expenses suit you better than actual costs for vehicles and working from home.
4. 4Enter the figures in the self-employment section of your online return, or complete the SA103S or SA103F PDF and send it with your paper SA100.

Short or full: the turnover test

HMRC's rule for the short page is simple: your annual business turnover was below the VAT registration threshold for the tax year and your tax affairs are relatively simple. Turnover means all your business income before expenses, not profit.

If you were above the threshold, or need to report things the short page doesn't have room for, use SA103F. Online, you don't choose: the return asks about your turnover and shows the right version.

Expenses and the cash basis

From the 2024/25 tax year the cash basis is the default for sole traders: you record income when you're paid and expenses when you pay them. You can opt out and use traditional accounting, which also counts money owed to you and bills you haven't paid yet at the year end.

For vehicles, you can claim either actual costs or HMRC's flat rate per business mile: 55p for the first 10,000 miles in a car or van and 25p after that, or 24p on a motorcycle. Once you use the flat rate for a vehicle, you keep using it while that vehicle is in the business.

Records behind the figures

You don't send records with the return, but HMRC expects you to keep a record of everything you sell and earn, your business expenses, and VAT and PAYE records if they apply. Receipts, bank statements and sales invoices are the proof. Keep them for at least five years after the 31 January deadline.

Common mistakes

• Filing the short page with turnover above the VAT threshold. HMRC's guidance is clear that the full page is for that.
• Claiming flat-rate mileage on a vehicle you've already claimed capital allowances on. HMRC doesn't allow both.
• Mixing business and personal transactions so you can't tell which is which. HMRC expects records that separate them.
• Not keeping receipts because the expenses total was entered as one figure. HMRC can ask to see the records behind it.