For UK contractors, your IR35 status makes a massive difference to your take-home pay. On a £120,000 annual fee in 2026/27, contracting Outside IR35 puts £74,654.38 in your pocket, compared to £62,907.40 Inside IR35. That is a difference of £11,746.98 a year. Here is the exact mathematical breakdown behind why that gap exists.
Key Takeaways for Contractors (2026/27)
- Outside IR35 Flexibility: Remuneration combines an optimal director salary of £12,570 with company dividend distributions.
- Corporation Tax Rates: 19% on profits under £50,000, 25% on profits over £250,000, with marginal relief applying between £50,000 and £250,000.
- Dividend Tax Rates: 10.75% (Basic Rate), 35.75% (Higher Rate), and 39.35% (Additional Rate) after the £500 tax-free dividend allowance.
- Employer NI: 15.0% on earnings exceeding the secondary threshold of £5,000 per year.
- Inside IR35 Burden: Deemed payments bear employer NI, apprenticeship levy, employee NI, and standard PAYE income tax out of the assignment rate.
1. What is IR35 and How Does Status Affect You?
IR35 (the Intermediaries Legislation, found in Chapters 8 and 10 of the Income Tax (Earnings and Pensions) Act 2003) was enacted by HMRC to combat “disguised employment”. Disguised employment occurs when a worker provides services through an intermediary (typically their own Personal Service Company, or PSC), but in practice works under terms equivalent to an employee.
When operating Outside IR35, HMRC recognizes your business as an independent commercial entity. Your PSC invoices the fee payer without employment tax deductions, and you manage company profits through a combination of deductible salary, allowable business expenses, and dividend distributions.
When an assignment is classified as Inside IR35, the fee payer or umbrella company must treat the entire contract fee (minus allowable employment costs) as deemed employment income, deducting PAYE Income Tax, Class 1 Employee NI, and Employer NI before paying the net balance.
2. The £120,000 Case Study: Step-by-Step Mathematical Comparison
To examine the concrete financial divergence between statuses, consider an independent consultant billing £120,000 in gross client fees during the 2026/27 tax year:
| Calculation Step / Pay Element | Outside IR35 (PSC Structure) | Inside IR35 (Deemed Employment) |
|---|---|---|
| Gross Contract Fee / Invoiced Turnover | £120,000.00 | £120,000.00 |
| Director Salary / PAYE Salary | £12,570.00 | £102,750.00 |
| Employer National Insurance (15% > £5,000) | £1,135.50 | £17,250.00 |
| Pre-Tax Corporate Profit | £106,294.50 | — |
| Corporation Tax (Marginal Relief) | £24,418.04 | — |
| Retained Profit for Dividends | £81,876.46 | — |
| Personal Income Tax (PAYE) | £0.00 | £35,432.00 |
| Employee National Insurance (Class 1) | £0.00 | £4,410.60 |
| Personal Dividend Tax | £19,792.08 | — |
| Total Annual Take-Home Pay | £74,654.38 | £62,907.40 |
| Monthly Equivalent Net Pay | £6,221.20 | £5,242.28 |
| Outside IR35 Financial Advantage | +£11,746.98 per year (+£978.91/month) | |
3. Why Does the Outside IR35 Structure Deliver Higher Retention?
The £11,746.98 retention difference is driven by three statutory tax mechanics:
- Absence of Employer NI on Dividends: Dividends are corporate profit distributions, not earnings, and are entirely exempt from National Insurance contributions for both company and shareholder.
- Lower Headline Dividend Tax Rates: While basic rate dividends are taxed at 10.75% and higher rate dividends at 35.75%, employment income incurs 40% income tax plus 2% employee NI plus 15% employer NI.
- Corporation Tax Deduction for Salary: The £12,570 director salary and £1,135.50 employer NI are recognized as legitimate corporate expenses, reducing the company’s taxable profit subject to Corporation Tax.