Self Assessment Tax Calculator UK 2025/26
Calculate your total tax liability as a sole trader, freelancer, or self-employed individual. Includes Income Tax, National Insurance, and payment deadlines.
2025/26 Tax Year: Personal Allowance £12,570. Basic Rate 20% up to £50,270. NI Classes: 2 (£3.45/wk), 4 (6%/2%).
Employment Income
Self-Employment Income
Rental Income
Dividend Income
Savings Income
Capital Gains
Other Deductions & Credits
Total Taxable Income£0.00
Total Income Tax£0.00
National Insurance£0.00
Total Liability£0.00
Tax Breakdown
| Income Source | Amount | Tax Rate | Tax Due |
|---|
| National Insurance Breakdown |
|---|
Enter your income and expense details above to see your Self Assessment tax liability.
⚠️ Self Assessment Deadlines 2025/26
📅 5 Oct 2026
— Register for Self Assessment (for 2025/26 tax year)
📄 31 Jan 2027
— File online tax return and pay tax owed
💷 31 Jul 2026
— First Payment on Account (if due)
💷 31 Jan 2027
— Second Payment on Account + balancing payment
Self Assessment Tax Calculator UK 2025/26
Use our free Self Assessment Tax Calculator to calculate exactly how much tax you’ll owe as a sole trader, freelancer, or self-employed individual in the UK. This comprehensive tool combines all your income sources — employment, self-employment, rental, dividends, savings, and capital gains — and applies the correct 2025/26 tax rates.
Who Needs to File Self Assessment?
You must file a Self Assessment tax return if you:
- Are self-employed as a sole trader with gross income over £1,000
- Own property and receive rental income over £2,500
- Have untaxed income (dividends, savings interest, tips, commissions)
- Earn over £100,000 from any source
- Are a company director (unless it’s a non-profit organisation)
- Have capital gains over the annual exemption (£3,000 for 2025/26)
- Receive income from abroad that’s taxable in the UK
- Need to claim relief for expenses or losses
2025/26 Income Tax Rates and Bands
| Tax Band | Income Range | Tax Rate |
|---|---|---|
| Personal Allowance | £0 – £12,570 | 0% |
| Basic Rate | £12,571 – £50,270 | 20% |
| Higher Rate | £50,271 – £125,140 | 40% |
| Additional Rate | Over £125,140 | 45% |
National Insurance for Self-Employed
| Class | When It Applies | 2025/26 Rate |
|---|---|---|
| Class 2 | Profits over £6,725/year | £3.45 per week |
| Class 4 | Profits over £12,570/year | 6% on £12,570-£50,270 2% above £50,270 |
Self Assessment Deadlines
Key dates for 2025/26 tax year:
- 5 October 2026: Register for Self Assessment
- 31 January 2027: File online return and pay tax owed
- 31 July 2026: First Payment on Account (if applicable)
- 31 January 2027: Second Payment on Account + balancing payment
Use our calculator to estimate your total tax liability before filing your return!