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New Umbrella Company Law From April 2026 — What Contractors Must Know
7 min read
For UK contractors, the difference between inside and outside IR35 is arguably the most financially significant determination HMRC can make about your working arrangement. But the impact isn't just about tax — it's about the fundamental economics of your day rate.
The Comparison: £500/Day
Let's assume 220 working days per year (52 weeks minus holiday). Gross annual: £110,000.
Outside IR35 (Using a Limited Company)
Working through your own limited company outside IR35, you extract income optimally as salary + dividends:
- Salary: £12,570 (no income tax)
- Dividends: remaining profit after Corporation Tax (25%)
- Approximate take-home from £110,000 revenue: ~£73,000
- Effective rate: ~34%
Inside IR35 (via Umbrella or PAYE)
Inside IR35, the intermediary (often an umbrella company) must treat your income as employment income:
- Income Tax at 40% (most of it above £50,270)
- Employee NI at 8%/2%
- Employer NI of 13.8% (deducted from your day rate before anything else)
- Umbrella fee: ~£25–£35/week
- Approximate take-home from £110,000 rate: ~£60,000–£62,000
The £10,000–£15,000 Difference
On the same day rate, working outside IR35 puts roughly £10,000–£15,000 more in your pocket annually compared to inside IR35. This is the number that makes IR35 determinations so consequential for contractors.
What Day Rate Do You Need Inside IR35?
To take home the same net income inside IR35 as outside, you'd need to charge approximately 20–25% more per day. On a £500/day outside IR35 equivalent, you'd need £600–£625/day inside IR35 to reach the same take-home.
Frequently Asked Questions
Can I challenge an inside IR35 determination?
Yes. Since April 2021, the determination is made by the end client (for medium and large businesses). You can request a Status Determination Statement (SDS) and formally disagree with it. However, in practice, many clients default to inside IR35 to avoid liability.
What happens if an IR35 determination is wrong?
If HMRC later determines that an inside IR35 working arrangement was actually outside, the liability falls on the end client (post-2021 rules). However, you could still face NIC liability if you've structured income in a way that assumed outside status.
Model the exact numbers with our IR35 Day Rate Calculator.