For sole tradersReady
Freelance designSA103 self-employment
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If you work for yourself, three figures give you a rough bill for the year. The return itself comes from your records: upload a bank statement or spreadsheet, snap your receipts, answer the few lines it can’t place, and file.
Invoices paid and cash taken during the tax year.
Materials, travel, tools, software, phone, a share of home costs. If under £1,000 we use the trading allowance instead.
Your pay before tax for the year. It decides which band your profit falls into.
Nothing you type is saved or sent anywhere.Estimated tax and National Insurance£0Type your figures and the number appears.
Income tax£0.00
Class 4 National Insurance£0.00
Of every £1 of profit0p
Uses 2025/26 income tax rates for England, Wales and Northern Ireland. It’s an estimate, not advice. The bill is due 31 January.
What counts, and what doesn’t.
Two rules decide what goes in your expenses.
What counts as an expense
Anything you spent only for the work: materials and stock, tools and equipment, travel between jobs, a van or car on the mileage rate, phone and internet, software, insurance, professional fees, advertising, and a fair share of the cost of working from home. Not your own wages, not taking clients out, not the drive to your usual workplace, not fines.
If your expenses come to under £1,000 you can take the £1,000 trading allowance instead and skip itemising. Swiftmore picks whichever leaves you better off.
Check a specific expense →Mileage or actual costs
If you drive for work you have two choices. A flat rate per business mile, 45p for the first 10,000 miles and 25p after that, which covers fuel, insurance, repairs and servicing. Parking and train fares go on top. Or the business share of what the vehicle actually costs to run, plus capital allowances, which is how the price of the vehicle itself is spread over a few years for tax.
Once you use the flat rate for a vehicle you stay with it for as long as you use that vehicle in the business, and you can’t start it on a vehicle you’ve already claimed capital allowances on. Swiftmore asks which you use and does the sums.
From profit to the bill.
Two rules turn your profit into a bill, and set when it’s due.
National Insurance
You pay Class 4 on profits above £12,570: 6% up to £50,270 and 2% on anything above that. Class 2 is treated as paid once your profits pass £6,845, so it costs you nothing and still counts towards your State Pension. National Insurance is the same everywhere in the UK. Only income tax differs in Scotland, which is what the toggle above is for.
Payments on account
If your bill is over £1,000 and less than 80% of your tax came through PAYE, HMRC asks you to pay towards next year as well: half on 31 January, on top of this year’s bill, and half on 31 July. Swiftmore shows you both dates and both amounts.
Work out your January bill →
What Swiftmore files for you.
Your main return (the SA100) and the self-employment pages (the SA103), plus the employment page if you also have a job and the capital gains page if you sold something. You get one summary of what you earned, spent and owe. You press submit, and HMRC’s reference is kept with the return.
Start free£99 when you file. No card to start.
Start freeFree to keep records. £99 for a tax year you read and file. No card to start.