Tax set-aside calculator
Self-employed and wondering how much to put aside for Self Assessment? Enter your estimated profit to see income tax, Class 4 National Insurance, a total, and a suggested monthly pot. Uses 2026-27 rates for England, Northern Ireland and Wales.
How this is worked out
- Personal Allowance: £12,570, reduced by £1 for every £2 of income above £100,000 (zero at £125,140).
- Income tax (England / NI / Wales): 20% on taxable income up to £37,700, 40% up to £125,140 taxable, 45% above that.
- Class 4 NI: 6% on profits between £12,570 and £50,270, then 2% above £50,270.
- Class 2: treated as paid if profits are at or above £7,105 — no cash cost in this calculator.
- Payments on account: if last year was similar, expect about half this total on 31 January and again on 31 July, unless the relevant amount is under £1,000 or more than 80% of the tax was deducted at source.
Sources: GOV.UK income tax rates, self-employed NI rates, payments on account. Scotland has different income tax bands.
Plan the whole year in a spreadsheet
The UK Self Assessment Tax Set-Aside & Payments-on-Account Planner adds an editable rate table, a monthly savings tracker, last-year PoA inputs and a payment calendar. It's coming to the Tidy Sheets shop soon.
Visit the shopComparing the £1,000 trading allowance with expenses? Try the free trading allowance calculator. Logging miles? Use the HMRC mileage allowance calculator. New to payments on account? Read the tax set-aside guide.