Sole Sums: Self Assessment

Sole Sums estimates your UK self assessment tax bill. It's a tax calculator for sole traders and the self-employed who want to know what they owe before 31 January. Put in your income and expenses. Sole Sums estimates your income tax, Class 4 National Insurance and student loan repayments. Then it shows what to pay on 31 January 2027 and 31 July 2027, including payments on account. WHAT IT WORKS OUT (FREE) • Income tax for the 2025/26 and 2026/27 tax years • Rates for England, Wales and Northern Ireland, and for Scotland • Class 4 National Insurance, plus voluntary Class 2 if you choose • Student loan: Plans 1, 2, 4 and 5, and the Postgraduate Loan • A PAYE job alongside your self-employment • The £1,000 trading allowance, if it suits you better than expenses • Your 31 January 2027 bill: the 2025/26 balancing payment plus the first 2026/27 payment on account • Your 31 July 2027 payment on account • When payments on account don't apply (the £1,000 and 80% rules) • How much of each pound to set aside for tax KEEP ON TOP OF IT (FREE) • Countdown to the 31 January self assessment deadline • A ready-to-file checklist • An income and expense log, using the expense categories from HMRC's self-employment pages (SA103). Up to 30 entries free. • Mileage calculator: 55p a mile for the first 10,000 miles in 2026/27 (45p before 6 April 2026), then 25p. Motorcycles 24p. • Use-of-home flat rate calculator: £10, £18 or £26 a month, based on the hours you work at home SOLE SUMS PRO A one-off purchase. No subscription. • Unlimited income and expense entries • Export your records as CSV • Export your records and estimate summary as PDF Restore Purchases is on the More tab (under Settings) and on the Pro screen. PRIVATE BY DESIGN • Works offline • No account and no sign-in • No bank link • No ads and no analytics • Your data is stored only on your device WHAT IT DOESN'T DO Sole Sums gives estimates, not tax advice. It doesn't file your tax return. You still file with HMRC yourself, or through an accountant or filing software. It doesn't cover dividends, savings interest, property income, capital gains, pension tax relief or the High Income Child Benefit Charge. If any of these apply to you, your real bill will be different. NOT A GOVERNMENT APP Sole Sums is not affiliated with, or endorsed by, HMRC or the UK government. It is made by Dylan Powell, an independent UK developer. Rates and thresholds come from GOV.UK and were checked on 3 November 2026: https://www.gov.uk/income-tax-rates https://www.gov.uk/scottish-income-tax https://www.gov.uk/self-employed-national-insurance-rates https://www.gov.uk/understand-self-assessment-bill/payments-on-account https://www.gov.uk/simpler-income-tax-simplified-expenses Privacy: https://solesums.impactlayer.workers.dev/privacy.html Support: https://solesums.impactlayer.workers.dev/support.html

First release. Estimate your 2025/26 and 2026/27 self assessment bill, including payments on account.