A side hustle is a job or occupation that brings in extra money alongside your full-time job. However, if you earn enough over the course of the year, you might consider opening a business account as you will likely need to pay tax on your side hustle earnings. Use our calculator to estimate how much.
Fill in the fields above to estimate deductions from your side hustle. Allowable expenses are essential costs that you can claim tax relief on but you can enter £0 if you have none.
1. Enter your total annual income from any employments you have – whether full-time or part-time.
2. Enter your total income from your side hustles – this might be counted as self-employment income by HMRC if it’s high enough.
3. Enter your total allowable expenses. Allowable expenses are essential business costs that you can claim tax relief on. IF you don’t have any, simply enter £0. Then press calculate!
Our calculator estimates how much tax you might be required to pay on your side hustle income if HMRC categorises it as taxable income. Anyone earning over the trading allowance – currently £1,000 – must fill in a self-assessment tax return and submit it to HMRC to be assessed.
Since income tax is based on your total income, the calculator combines your income from employment with your side hustle earnings. It works out how much income tax you would pay in total on all your income and how much income tax you would be paying if it was just your main employment – therefore showing how much additional income tax you would be paying due to your side hustle earnings.
In the 2025/2026 tax year, you have to pay Class 4 National Insurance on any self-employment profits over £12,570.
The rate for profits between £12,570 and £50,270 is 6%. You also pay 2% on anything above the Upper Profits Limit of £50,270.
The calculator will show the Class 4 contributions you should pay if this applies to you. It does not include Class 2 contributions, as self-employed taxpayers are no longer required to pay Class 2 NICs (although they can voluntarily in some situations).
The trading allowance is £1,000 for the 2025/2026 tax year, which means you can earn this amount through self-employment (selling goods/services) and casual services such as babysitting or gardening without having to submit a self-assessment tax return.
Side hustles are a popular way to earn extra money, but new Finder research reveals that more than half of Brits (53%) incorrectly guessed the amount you can earn from a side gig such as selling goods online or babysitting before you need to fill in a self-assessment tax return.
The trading allowance is £1,000 a year, but 1 in 5 Brits (22%) believe you can earn more than £4,000 a year, while almost 1 in 10 Brits (9%) believe you can earn more than £10,000 without reporting the income to HMRC.
What’s more, according to separate research earlier this year, 38% of UK adults reported earning an average of £20 or more per week from side hustles. This works out at more than the trading allowance*, which is £1,000 a year.
Despite this lack of knowledge about the trading allowance, more than 2 in 5 Brits (43%) reported having a side hustle as an additional source of income in 2024. The average side hustle income is estimated to be £900 a month (or £10,800 a year).
According to a 2024 Finder survey, around 7 in 10 members of generation Z (aged 18-27) make money from a side hustle. However, the new research from Finder reveals that this generation is the least likely to understand the tax rules surrounding side hustles, with only a third (33%) correctly identifying the trading allowance compared to a UK average of 47%.
Millennials (aged 28-43) are the second most likely to be unaware of the tax rules, with only 2 in 5 (40%) correctly identifying the trading allowance. This is despite the fact that 63% of millennials earn money from a side hustle.
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