How much more do I take home outside IR35 at £600/day?
At £600/day over 220 billable days (£132,000 contract revenue), outside IR35 nets you £79,613 per year through a limited company, versus £73,142 per year inside IR35 via an umbrella. That is a difference of £6,471 per year (8.8% more), before accounting for accountancy fees you'd pay either way.
