FREE UK SOLE TRADER TOOL
Estimate your 2026/27 sole trader profit, Income Tax and Class 4 National Insurance with this free calculator for England, Wales and Northern Ireland.
2026/27 ESTIMATE
Self-employed tax and NI calculator
For England, Wales and Northern Ireland. Payments on account are not included.
Your figures stay in your browser and are not sent to Real Key Accountancy.
Enter expenses that are allowable for tax. Do not include personal spending.
For example, employment or pension income before tax. This tool does not calculate savings, dividends or property-specific rules.
For example, PAYE deducted from employment. Do not include National Insurance.
Self-employed tax calculation example
For example, enter £50,000 annual turnover and £12,000 allowable business expenses, with no other taxable income or tax already deducted. The calculator estimates:
- Self-employed profit: £38,000
- Estimated Income Tax: £5,086
- Estimated Class 4 National Insurance: £1,526
- Estimated total remaining: £6,612
This worked example uses the 2026/27 rates for England, Wales and Northern Ireland. It excludes payments on account and the other adjustments listed in the calculator notice, so an actual Self Assessment payment may be different.
How the self-employed tax calculator works
The calculator first deducts allowable business expenses from turnover to estimate your sole trader profit. It then applies the 2026/27 Income Tax bands for England, Wales and Northern Ireland and estimates Class 4 National Insurance on self-employed profit.
Other taxable income is included because it can use your Personal Allowance and tax bands before or alongside business profit. Enter tax already deducted so the result can show a simplified remaining amount.
2026/27 Income Tax rates used
| Band | Taxable income | Rate |
|---|---|---|
| Personal Allowance | Up to £12,570 | 0% |
| Basic rate | Next £37,700 | 20% |
| Higher rate | £37,701 to £125,140 taxable income | 40% |
| Additional rate | Above £125,140 taxable income | 45% |
The Personal Allowance is reduced by £1 for every £2 of adjusted net income above £100,000 and is normally fully removed at £125,140. Scottish Income Tax bands differ, so this tool should not be used by Scottish taxpayers.
2026/27 self-employed National Insurance
Class 4 National Insurance is estimated at 6% on profits over £12,570 up to £50,270 and 2% on profits above £50,270. If profits are at least £7,105, Class 2 is generally treated as paid to protect your National Insurance record without a payment. If profits are below £7,105, voluntary Class 2 may be available at £3.65 a week.
What expenses can a sole trader claim?
Allowable expenses can include eligible business travel, office costs, insurance, professional fees, advertising, software and some use-of-home costs. Personal spending and the private proportion of mixed costs are not normally allowable. Capital purchases and vehicle costs may need separate treatment.
Good records make the calculation more reliable. Our sole trader accountancy support in Wolverhampton and small business accountancy services can help keep income and expenses organised.
Why the final Self Assessment bill may be different
- Payments on account may be added
- Student or postgraduate loan repayments may apply
- Pension contributions and Gift Aid can change tax bands
- Capital allowances may differ from accounting expenses
- Trading losses and loss relief are not included
- Savings, dividends and property income can use separate rules
- Benefits, marriage allowance and High Income Child Benefit Charge are excluded
How Real Key Accountancy can help
- Organise digital bookkeeping records
- Track business income and allowable expense evidence
- Prepare non-statutory sole trader accounts
- Support VAT and Making Tax Digital record keeping
- Identify when appropriately authorised tax advice is needed
Explore our sole-trader bookkeeping support, bookkeeping packages, VAT Registration Threshold Checker and MTD Start Date Checker. You can also contact Real Key Accountancy for bookkeeping and record support.
Official rates and guidance
Rates were checked in August 2026 against HMRC Income Tax rates and HMRC self-employed National Insurance rates. Always check current official guidance before making financial decisions.
Frequently asked questions
How much tax will I pay if I am self-employed?
The amount depends on taxable profit, other income, allowances and personal circumstances. Enter turnover and allowable expenses above for a simplified 2026/27 estimate of Income Tax and Class 4 National Insurance.
How much should a self-employed person set aside for tax?
There is no single percentage suitable for everyone. Use the calculator result as an initial estimate and remember that payments on account, student loans and other adjustments can increase the amount due. Consider obtaining advice based on your circumstances.
Is sole trader tax based on turnover or profit?
Income Tax and Class 4 National Insurance are generally based on taxable profit after allowable expenses, not gross turnover.
Does this include payments on account?
No. Payments on account are excluded because they depend on your previous bill and circumstances. They can make the January payment larger than the tax estimate shown.
Can limited-company directors use this calculator?
No. Salary, dividends and Corporation Tax follow different rules. This calculator is designed for self-employed sole trader profit.