Contractor Guide

IR35 Explained

Everything contractors need to know about IR35, including status determination, inside vs outside IR35, and the tax implications for your limited company.

Inside vs Outside IR35

Inside IR35

"Deemed employment"

You're treated as an employee for tax purposes. Tax and NI are deducted at source, similar to PAYE.

Income Tax20-45%
Employee NI12% / 2%
Employer NI13.8%
Dividend tax efficiencyNo
Effective rate (£60k)~40-45%

Outside IR35

"Genuine business"

You operate as a genuine business. You can use salary + dividends strategy for tax efficiency.

Corporation Tax19-25%
Salary (minimal)~£12,570
Dividend tax8.75-39.35%
Dividend tax efficiencyYes
Effective rate (£60k)~25-30%

What Determines Your Status?

Factors Pointing Inside IR35

Control over how, when, and where you work

No right to send a substitute

Mutuality of obligation (ongoing work expectation)

Using client's equipment and tools

Working exclusively for one client

Being integrated into the client's organisation

No financial risk if project fails

Factors Pointing Outside IR35

Control over your own methods and schedule

Genuine right of substitution

Project-based work with defined deliverables

Using your own equipment and tools

Working for multiple clients

Not integrated into the organisation

Financial risk and business costs

No Single Factor Is Decisive

HMRC looks at the whole picture. Having one "outside" factor doesn't guarantee you're outside IR35. The overall working arrangement is what matters, and all factors are weighed together.

The Three Key Tests

1. Control

Does the client control how, when, and where you work? Employees have less control over their working arrangements.

Outside IR35: You decide your own methods, hours, and location. Client only specifies the end result.

2. Substitution

Can you send someone else to do the work? A genuine right of substitution is a strong indicator of self-employment.

Outside IR35: You have an unfettered right to send a qualified substitute, and would pay them yourself.

3. Mutuality of Obligation

Is there ongoing obligation to offer and accept work? Employees have mutual obligations; contractors work project-to-project.

Outside IR35: No obligation to accept future work. Client has no obligation to offer more work.

Off-Payroll Working Rules (April 2021)

Since April 2021, medium and large private sector clients are responsible for determining IR35 status for contractors working through their own limited companies.

Client Responsibilities

  • Determine status for each engagement
  • Provide Status Determination Statement (SDS)
  • Pass SDS down the supply chain
  • Respond to status challenges

Who Pays the Tax?

  • Fee-payer deducts PAYE and NI if inside IR35
  • Usually the agency or client paying your company
  • 5% expense allowance deducted before tax

Small Company Exemption

If your end client is a small private company, YOU determine your own IR35 status. A company is "small" if it meets 2 of these 3 criteria:

<£10.2m
Annual turnover
<£5.1m
Balance sheet total
<50
Employees

Frequently Asked Questions

Compare Inside vs Outside IR35

See the exact difference in take-home pay for your day rate with our IR35 calculator.