Inside vs Outside IR35: The Difference and What It Means for Your Pay

Few phrases matter more to a contractor than “inside” or “outside” IR35 — because the answer can change your take-home pay by a fifth or more. Here’s exactly what each means and how to tell them apart.

The short version

• Outside IR35 — HMRC accepts you’re running a genuine business. You’re taxed as one: a small salary plus dividends through your limited company, with business expenses. This is the efficient contracting setup.
• Inside IR35 — HMRC treats you as a “disguised employee” for that contract. You’re taxed broadly like an employee — Income Tax and National Insurance on most of your income, and little of the limited-company advantage.

It’s decided per contract, based on the reality of the working relationship — so you can be outside on one engagement and inside on another.

What it does to your pay

This is why contractors care so much. On the same day rate:

• Outside IR35: small salary + dividends + expenses → the most you legitimately keep. See it with our salary & dividend calculator.
• Inside IR35: employee-style tax on most of your income → typically 20–25% less take-home.

That difference is large enough to change whether a contract is worth taking — which is why status should be checked before you sign, not after.

The tests that decide it

A contract is more likely to be outside IR35 if:

• You have a genuine right of substitution (you could send someone else)
• You control how you do the work, not the client
• There’s no mutuality of obligation — they don’t have to give you work, you don’t have to accept it
• You take financial risk, use your own equipment, and work for multiple clients
• You’re not “part and parcel” of the organisation (no staff perks, line management, etc.)

It’s more likely inside if you look and work like an employee — fixed hours, client direction, an ongoing obligation, integrated into the team. We go deeper in IR35 explained.

Inside IR35? Consider your options

If a contract is genuinely inside IR35, the limited-company tax advantage largely disappears for that work. Your realistic options are:

• Work through your limited company anyway (with tax deducted at source), or
• Use an umbrella company, which can be simpler for consistently-inside work — see umbrella company explained

The right choice depends on your mix of contracts and your plans.

Get your status right — and evidenced

The cost of getting IR35 wrong isn’t just lost take-home; an incorrect “outside” determination can mean a backdated tax bill if HMRC challenges it. The key is assessing each contract honestly and keeping evidence to back it up.

Our accountants for contractors review your contracts and working practices, help you understand and document your IR35 position, and structure your pay efficiently where you’re legitimately outside — so you keep what you’ve earned and stay defensible.