Self Employed Tax Calculator UK 2026
15 August 2026
Work out your 2025/26 self-employed tax with our free UK calculator. Enter profit to see income tax, NI and what you owe.
What is a Self Employed Tax Calculator?
A self employed tax calculator is a free online tool that helps UK freelancers, contractors and sole traders estimate their tax bill. Instead of guessing how much to set aside for HMRC, you enter your annual turnover and allowable expenses, and the calculator does the rest. It works out your taxable profit, deducts your personal allowance and then applies the correct rates of Income Tax and National Insurance. Some advanced calculators also factor in student loan repayments and Marriage Allowance. Using one regularly gives you a clear picture of your tax liability, helping you budget, plan for payments on account and avoid year-end surprises.
How the Calculator Works: From Turnover to Profit
The key to an accurate calculation is understanding your profit. First, add up all the money your business received during the tax year (turnover). Then deduct any allowable expenses you’ve incurred, such as office supplies, travel, software subscriptions or a portion of your home utility bills. The result is your taxable profit. Our calculator uses this figure to apply your tax-free Personal Allowance of £12,570 and then taxes the remaining profit at the appropriate Income Tax bands. You’ll also see your Class 4 National Insurance contribution, calculated at 6% on profits between £12,570 and £50,270, and 2% above that.
What Taxes Does It Calculate?
The main taxes for self-employed people in the UK are Income Tax and National Insurance. Income Tax is charged at 20% on profits from £12,570 to £50,270, 40% on profits from £50,271 to £125,140, and 45% above that. Class 4 National Insurance is charged at 6% on profits between £12,570 and £50,270, with an additional 2% on profits above £50,270. Since April 2024, Class 2 National Insurance has been abolished, so you no longer need to pay a flat fee. The calculator also estimates any student loan repayments if you indicate you have one, using the threshold applicable to your loan plan (Plan 1, Plan 2 or Plan 4).
Tax Rates and Allowances for 2025/26
For the 2025/26 tax year, the Personal Allowance remains at £12,570, meaning you pay no Income Tax on profits up to that amount. The basic rate of 20% applies to profits from £12,571 to £50,270. The higher rate of 40% applies to profits from £50,271 to £125,140, and the additional rate of 45% applies to any profit above £125,140. These thresholds are frozen, so if your profits have grown, you may be paying more tax than in previous years. Our calculator is updated with these current rates, so you can trust the estimate to reflect HMRC’s rules for the 2025/26 tax year and plan accordingly.
How to Lower Your Self Employed Tax Bill
Using the calculator highlights why claiming all your allowable expenses is vital. Common deductions include office costs, equipment, business travel, professional fees, and a proportion of your phone and broadband bills. If you work from home, you can claim a simplified flat rate of £26 per month based on the number of months you worked, or you can calculate actual costs. Don’t forget pension contributions – they reduce your taxable profit. Making a personal pension contribution is one of the most tax-efficient ways to save for retirement while lowering your immediate tax liability. Always keep receipts and records to support your claims, as HMRC requires documentation.
FAQ
Start with your total turnover, subtract allowable expenses to get taxable profit. Deduct your £12,570 personal allowance, then apply Income Tax rates (20%, 40%, 45%). Add Class 4 National Insurance (6% on profits between £12,570 and £50,270, 2% above). Our calculator does this automatically.