No. The result is extra annual Income Tax only. Review Class 4 National Insurance and other Self Assessment amounts separately.
Side Hustle Tax Calculator UK
Enter your values below to get the result first, then scroll for the full explanation and guidance.
Additional annual Income Tax on trading profit
£1,800.002026/27 standard annual comparison
Additional annual Income Tax on trading profit: £1,800.00 (2026/27 standard annual comparison)
Compare Income Tax on employment plus taxable trading profit with tax on employment alone; the Personal Allowance is used once.
Additional Income Tax only
Compare Income Tax on employment plus taxable trading profit with tax on employment alone; the Personal Allowance is used once.
Result snapshot
A quick visual read of the values behind this result.
Trading turnover£10,000.00
Trading allowance£1,000.00
Taxable trading profit£9,000.00
Income Tax on employment alone£3,486.00
Income Tax on combined income£5,286.00
Recommended next checks
- →Confirm the trading allowance or actual expense eligibility and your total taxable income.
- →Check Class 4 NI, student loans and Self Assessment payments separately.
- Trading turnover
- £10,000.00
- Trading allowance
- £1,000.00
- Taxable trading profit
- £9,000.00
- Income Tax on employment alone
- £3,486.00
- Income Tax on combined income
- £5,286.00
Excludes Class 1 and Class 4 NI, savings, dividends, losses, pension reliefs, special PAYE codes and tax already paid. Not a Self Assessment bill.
Try different values to compare results.
Enter your employment income and side-hustle turnover, then select an eligible trading allowance or actual allowable expenses. The tool estimates the additional annual Income Tax on trading profit, not all taxes and National Insurance due.
Additional annual Income Tax on trading profit
£1,800.002026/27 standard annual comparison
Additional annual Income Tax on trading profit: £1,800.00 (2026/27 standard annual comparison)
Compare Income Tax on employment plus taxable trading profit with tax on employment alone; the Personal Allowance is used once.
Additional Income Tax only
Compare Income Tax on employment plus taxable trading profit with tax on employment alone; the Personal Allowance is used once.
Result snapshot
A quick visual read of the values behind this result.
Trading turnover£10,000.00
Trading allowance£1,000.00
Taxable trading profit£9,000.00
Income Tax on employment alone£3,486.00
Income Tax on combined income£5,286.00
Recommended next checks
- →Confirm the trading allowance or actual expense eligibility and your total taxable income.
- →Check Class 4 NI, student loans and Self Assessment payments separately.
- Trading turnover
- £10,000.00
- Trading allowance
- £1,000.00
- Taxable trading profit
- £9,000.00
- Income Tax on employment alone
- £3,486.00
- Income Tax on combined income
- £5,286.00
Excludes Class 1 and Class 4 NI, savings, dividends, losses, pension reliefs, special PAYE codes and tax already paid. Not a Self Assessment bill.
Try different values to compare results.
Table of Contents
Table of Contents
About Side Hustle Tax Calculator UK
Side Hustle Tax Calculator UK helps you work through the main numbers for this topic quickly with a simple input flow and an instant result.
Use the calculator result as a practical starting point, then review the explanation and assumptions on the page if you want more context.
How extra Income Tax is estimated
Taxable trading profit is turnover less the chosen deduction. The estimate subtracts Income Tax on employment alone from Income Tax on employment plus trading profit, so the Personal Allowance is applied only once. GBP 30,000 employment income plus GBP 9,000 trading profit adds GBP 1,800 standard Income Tax in England.
Self-employment National Insurance, any Class 1 NI on employment, tax already paid, student loans, reliefs and payments on account are outside this narrow comparison. HMRC may calculate a different final liability.
Formula explained
Calculation flow
This calculator is structured for fast UK-focused estimates with clear inputs, repeatable logic, and instant results.
Formula
Input values -> calculation engine -> instant result
How the result is built
1Enter the values requested in the form.
2The calculator applies the configured formula logic.
3The result updates instantly with a breakdown.
4Use the output to compare scenarios quickly.
Example
Example: GBP 30,000 employment income plus GBP 10,000 trading turnover, less an eligible GBP 1,000 allowance, adds GBP 1,800 Income Tax in England; National Insurance is excluded.
Assumptions
- One self-employed trade and one annual employment-income amount in 2026/27, taxed under standard ordinary-income bands.
- Claim an eligible GBP 1,000 trading allowance or actual eligible expenses, never both; check restrictions before selecting the allowance.
- The result is additional Income Tax only, not Class 4 or Class 1 NI, student loans, PAYE withholding, or the final Self Assessment payment.
Source basis
- UK-focused calculator flow
- Structured input validation
- Instant result breakdowns
FAQ
Common questions
Trust and notes
Assumptions and important notes
This calculator is designed to give a fast estimate using the method shown on the page. Results are most useful when your inputs are accurate and the tool matches your situation.
Use the result as guidance rather than a final diagnosis or professional decision. If the result could affect health, legal, financial, or compliance decisions, verify it with a qualified source where appropriate.
- One self-employed trade and one annual employment-income amount in 2026/27, taxed under standard ordinary-income bands.
- Claim an eligible GBP 1,000 trading allowance or actual eligible expenses, never both; check restrictions before selecting the allowance.
- The result is additional Income Tax only, not Class 4 or Class 1 NI, student loans, PAYE withholding, or the final Self Assessment payment.
Method
UK calculator guidance
Last reviewed
April 17, 2026