Free Self Assessment Calculators for UK Taxpayers
Work out your tax bill, check whether you need to file, and see what a late return could cost. Four free tools from qualified accountants, using the 2025/26 rates.
Choose a calculatorGet a fixed quote
Choose your calculator
Pick the one that matches your situation. Each gives an instant estimate with a clear breakdown.
Self-employed tax calculator
Landlord tax calculator
Penalty calculator
Do I need to file a tax return?
How the calculators work
No jargon and nothing to install.
Enter your figures
Add income, expenses or dates. Nothing is stored or sent anywhere.
See the breakdown
Get Income Tax, National Insurance, penalties or a clear yes or no, line by line.
Plan with confidence
Know how much to set aside, and when payments on account are due.
Hand it to us if you like
Our accountants prepare and file your return for a fixed fee.
2025/26 rates at a glance
The figures every calculator on this page uses (England, Wales and Northern Ireland).
| Item | 2025/26 |
|---|---|
| Personal Allowance | £12,570 (reduces above £100,000) |
| Basic rate 20% | On the next £37,700 of taxable income |
| Higher rate 40% | Up to £125,140 |
| Additional rate 45% | Above £125,140 |
| Class 4 National Insurance | 6% from £12,570 to £50,270, then 2% |
| Trading and property allowance | £1,000 each |
| Online filing and payment deadline | 31 January 2027 |
Frequently asked questions
Are these Self Assessment calculators free?
Yes. All four calculators are free to use, need no sign-up and do not store the figures you enter.
Are the calculators accurate for 2025/26?
They use the 2025/26 rates for England, Wales and Northern Ireland: a £12,570 Personal Allowance, 20%, 40% and 45% Income Tax bands, and Class 4 National Insurance at 6% and 2%. They give estimates, not a final tax bill. Scottish rates differ.
Which calculator should I use first?
If you are unsure whether you must file, start with the ‘Do I need to file a tax return?’ checker. If you already file, use the self-employed or landlord calculator to estimate your bill, and the penalty calculator if you have missed a deadline.
What is the Self Assessment deadline?
The online filing and payment deadline for the 2025/26 tax year is 31 January 2027. Paper returns are due earlier, on 31 October 2026.
Can an accountant prepare my return for me?
Yes. Our accountants prepare and file your return for a fixed fee agreed before you pay, with packages from £199 plus VAT. You can get a quote in a couple of minutes.
Prefer to leave it to the experts?
Fixed fees from £199 plus VAT, agreed before you pay. We prepare, check and file your return.
Estimates for illustration only, using England, Wales and Northern Ireland rates (Scottish rates differ). This is general information, not personal tax advice. Check current HMRC guidance. See also our pricing, guides and free tax reminders.
