About SideHustleTax
An independent, UK-based tool for people who earn a bit on the side and just want a straight answer.
Why this exists
Millions of people in the UK earn money outside their main job — selling on Vinted or Etsy, renting out a room on Airbnb, driving for Uber, doing a bit of freelance work. For most of them, the tax situation is genuinely confusing: Will HMRC know? Do I need to register? How much do I actually owe?
Existing calculators tend to apply a flat tax rate, ignore the trading allowance, or produce a number without explaining how they got there. This one is built differently. It uses the correct marginal-rate approach — stacking your side-hustle profit on top of your salary to find the exact bands it crosses — which is the only way to get the right answer.
Who built it
SideHustleTax is an independent project built and maintained in the UK. It is not affiliated with HMRC, any accountancy firm, or any financial product provider. There are no investors, no board, and no commercial agenda behind the calculator itself.
How the maths is verified
Every formula is sourced directly from HMRC's published guidance and GOV.UK: income tax bands from gov.uk/income-tax-rates, Scottish rates from gov.uk/scottish-income-tax, Class 4 NI from HMRC's published NI rates, and the trading allowance rules from HMRC's online platform guidance. The calculator includes a suite of eight regression tests that run automatically in development to verify the maths against known correct outputs.
What this is not
SideHustleTax is a calculator, not a tax adviser. It provides a general estimate based on the figures you enter and the published HMRC rules for 2026/27. It does not account for every individual circumstance — for example, pension contributions that affect your adjusted income, marriage allowance, or income from property. If your situation is complex, please consult a qualified accountant or tax adviser.
Nothing you enter is stored, sent anywhere, or used for any purpose other than displaying your result in your browser. Your inputs are saved locally in your browser only so the calculator remembers your figures if you return.
Keeping it up to date
Tax bands are currently frozen until April 2028 per the Autumn Statement 2022 announcement. We review and update the calculator every April following the Budget and HMRC's published rate confirmations.