IR35 Calculator: How It Works and How to Use It
Compare estimated UK contractor take-home pay inside IR35 versus outside IR35 through a limited company.
Like every tool on UltimateTools, it runs instantly in your browser, updates as you type, and doesn't require an account or sign-up to use.
What it calculates
Compare contractor take-home pay inside vs. outside IR35.
Whether you think of it as a "ir35 calculator" tool, a "inside outside ir35 or contractor take home pay" tool, or simply the IR35 Calculator, this page covers the same calculation.
You can find it at any time on the IR35 Calculator page, where the calculator sits above a full explanation of the method it uses.
Tips for an accurate result
Factor in any pre-tax deductions (retirement contributions, health insurance) separately, since they change the taxable base, not just the final total.
Recalculate after any raise, bonus, or change in filing status — last year's numbers rarely still apply.
Remember that take-home estimates rarely include every deduction your employer applies — treat the output as a close estimate, not a guarantee.
If you're self-employed or freelance, remember employer-side taxes usually fall on you too — don't reuse an employee-focused estimate as-is.
Related tools worth trying
If you found the IR35 Calculator useful, Invoice Generator, Freelance Rate Calculator, UK Take-Home Pay Calculator cover closely related ground and are worth a look next.