IR35 Calculator

Unsure whether IR35 will hit you hard? See exactly how much take-home pay you’d lose by falling inside IR35 compared to operating outside — so you can make an informed decision about your contracts.

How to use this calculator
Day rate
£
Inside IR35 Outside IR35
Gross revenue – –
Employer NI – –
Income tax – –
Employee NI – –
Corporation tax – –
Dividend tax – –
Annual take home – –
Effective tax rate – –

Understanding IR35 and Its Impact on Contractors

IR35 (also known as the off-payroll working rules) is legislation designed to prevent tax avoidance by contractors who would otherwise be employees. If you’re deemed inside IR35, you pay similar tax and NI as an employee — significantly reducing your take-home pay.

Inside vs Outside IR35

When outside IR35, contractors can extract profits through a mix of salary and dividends, paying less tax overall. When inside IR35, the end client or agency deducts PAYE tax and NI at source, and employer’s NI is also payable — often from your fee.

The Financial Impact

A contractor on a £500/day rate working 220 days can take home roughly £85,000–£90,000 outside IR35 versus around £65,000–£70,000 inside IR35 — a difference of up to £20,000 per year. Use this calculator to see the exact impact on your day rate.