Side hustle tax calculator
See how much Income Tax and National Insurance your side income adds on top of your job, for the 2026 to 2027 tax year, and how much of it you keep.
- Free, no sign-up
- 2026 to 2027 tax year
- Nothing you type leaves your browser
Put this aside for HMRC
£1,000
That's £1,000 Income Tax, due by 31 January after the tax year ends. You keep £4,500.
- You keep£4,500
- Income Tax£1,000
- National Insurance£0
- Expenses£500
We've taken off the £1,000 trading allowance instead of your expenses, because it saves you more. You can't claim both. With your salary, the top of your side income is taxed at the basic rate.
How side hustle tax worksHow we work it out
It's an estimate, not tax advice. If the numbers are close, check with an accountant.
Your side profit is added on top of your salary, so it's taxed at whichever rate your salary has already reached. We work out the tax on your salary and side profit together, then take away the tax on your salary alone. The difference is what your side hustle adds.
You can either take the £1,000 trading allowance off your income or claim your actual expenses, not both. We use whichever saves you more. If your side income is £1,000 or less, the allowance covers it completely.
Class 4 National Insurance is worked out on your business profit only: 6% on profit between £12,570 and £50,270 and 2% above that. Everything stays in your browser.
Questions people ask
Something we haven't covered? Ask us.
Do I pay tax on a side hustle under £1,000?
Usually not. The trading allowance covers the first £1,000 of gross trading income each tax year, so you don't need to report it or pay tax on it.
Why is my side income taxed at 40%?
Your side profit sits on top of your salary. If the two together go over £50,270 (or the Scottish higher rate threshold), the part above it is taxed at the higher rate.
When do I need to tell HMRC?
If your gross trading income is over £1,000 in a tax year, register for Self Assessment by 5 October after that tax year ends and file a return by 31 January.
Does this include National Insurance on my salary?
No. Your employer already takes Class 1 National Insurance from your wages. This shows the Class 4 National Insurance on your business profits, which starts once profits are over £12,570.
Read this next
Free guides that explain the numbers in more detail.
- Do you pay tax on a side hustle in the UK?7 minute readWhen side income becomes taxable, how the £1,000 trading allowance works, when to register with HMRC and how much tax you'll pay on top of a salary.
- How to register as self-employed in the UK (sole trader)6 minute readWhen you need to register as a sole trader with HMRC, the 5 October deadline, what you need, how long your UTR takes and what happens next.
- Self-employed tax explained: what you pay and when (UK)7 minute readHow self-employed tax works in the UK: profit vs income, allowable expenses, Income Tax and National Insurance rates, payments on account and key dates.
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