Self-employed calculators
Tools for sole traders, freelancers, side hustles and landlords. Estimate how much to put aside for Income Tax and Class 4 National Insurance, compare the £1,000 trading allowance with your actual expenses, work out a mileage claim at HMRC rates and check your turnover against the £90,000 VAT threshold. You can also add statutory interest to late invoices, see the tax on rental profit, check whether and when Making Tax Digital for Income Tax applies to you, and add every Self Assessment deadline to your calendar.
- Tax set-aside calculatorEstimate Income Tax and Class 4 NI on your profit, plus a monthly pot and a payments-on-account note.
- £1,000 trading allowance calculatorClaim the allowance or your actual expenses, and do you need to register for Self Assessment?
- Mileage allowance calculatorYour HMRC simplified mileage claim at 55p then 25p a mile (2026-27), or 24p for motorcycles.
- VAT calculator & threshold checkerAdd or remove VAT at 20%, 5% or 0%, then check your rolling 12-month turnover against the £90,000 threshold.
- Late payment interest calculatorStatutory interest (8% + base rate) and the £40/£70/£100 compensation on an overdue business invoice.
- Rental income tax calculatorFor landlords: taxable rental profit, the £1,000 property allowance vs actual expenses, and the 20% mortgage interest credit.
- Making Tax Digital for Income Tax checkerDo you need MTD for Income Tax, and from when? Over £50,000 from April 2026, £30,000 from 2027 and £20,000 from 2028.
- Tax deadlines calendarEvery Self Assessment, Making Tax Digital and tax-year deadline, free to subscribe to in Google, Apple or Outlook.
Related guides
- How much tax to set asideHow Income Tax and Class 4 NI add up, payments on account with a first-year example, and the key deadlines.
- £1,000 trading allowance guideFull and partial relief, allowance vs expenses, and when you need Self Assessment.
- Mileage & expenses guideHMRC mileage rates, what the flat rate covers, working-from-home flat rates and common allowable costs.
- Landlord rental income tax guideProperty allowance vs expenses, allowable costs, the 20% mortgage interest credit and Making Tax Digital dates.
- Late paying clients guideWhen an invoice is legally late, statutory interest, fixed compensation and how to chase politely.
Prefer pen and paper? Our printed Self Employed Accounts Book (an April-to-March income and expenses cash book) and Mileage Log Book are £7.99 each on Amazon. Both are also available from Lulu (£9.99 each): the Self Employed Accounts Book and the Mileage Log Book. Landlords can keep rent and costs in our printed Rental Income & Expenses Record Book (£7.99).
Want it all in a spreadsheet?
Straight Sums makes simple Excel and Google Sheets templates for UK side hustles, the self-employed and household budgets.