How much tax will I pay on a side hustle?

Updated for 2026/27 · No signup · Estimate only, not financial advice

If you already have a full-time job, your side hustle income is added on top of your salary and taxed at your highest marginal rate — usually 20% or 40% — plus Class 4 National Insurance if your side income is self-employed, with no extra Personal Allowance to use.

Why side income is taxed differently

Your Personal Allowance is already used up by your main job in most cases, so side hustle profit is taxed from the first pound at whatever rate your total income falls into. If your combined income crosses £50,270, the side income above that point is taxed at 40%.

Do I need to register for Self Assessment?

If your side hustle income is over £1,000 in a tax year (the Trading Allowance), you generally need to register for Self Assessment and declare it, even if you also have a full-time PAYE job.

Calculate my side hustle tax

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FAQ

Do I pay tax on a side hustle under £1,000?

No — the £1,000 Trading Allowance means side income under this amount in a tax year is tax-free and doesn't need to be declared.

What tax rate applies to side hustle income?

It's taxed at whatever your highest marginal rate is once combined with your main job's income — typically 20% or 40% Income Tax, plus 6% Class 4 National Insurance if self-employed.

Do I need to register as self-employed for a side hustle?

If your side income exceeds £1,000 in a tax year, yes — you need to register for Self Assessment with HMRC, even alongside a full-time PAYE job.