About
Why we built Contractor Tax Tools
Working for yourself is hard enough without wrestling a spreadsheet every time you need to know what you'll actually take home. Contractor Tax Tools exists to answer the money questions contractors and freelancers ask most — clearly, accurately, and for free.
What we make
We focus on two audiences with very different tax systems:
- UK contractors — our IR35 calculator and status checker helps you understand whether a contract is inside or outside IR35 and what each status does to your take-home pay.
- US freelancers — our self-employment tax calculator estimates the 15.3% SE tax on 1099 income and your quarterly payments.
Our principles
- Show the working. Every result breaks down the calculation so you can check it, not just trust it.
- Stay current. We update figures for each tax year — US 2026 and UK 2026/27 — and cite the rules behind them.
- Respect your privacy. Calculations run in your browser. We never see or store the numbers you type.
- Be honest about limits. These are estimates and educational tools, not a replacement for a qualified accountant. See our disclaimer.
A note on accuracy
Tax rules are detailed and change often. We work hard to keep our calculators correct and transparent about their assumptions, but they can't capture every personal circumstance. If you spot something that looks wrong, please tell us — we genuinely want to fix it.