How much more do I take home outside IR35 at £800/day?
At £800/day over 220 billable days (£176,000 contract revenue), outside IR35 nets you £100,054 per year through a limited company, versus £90,375 per year inside IR35 via an umbrella. That is a difference of £9,679 per year (10.7% more), before accounting for accountancy fees you'd pay either way.
