IR35 Take-Home Calculator: Inside vs Outside
🧮 Inside vs Outside IR35 — Annual Take-Home Comparison
✅ Outside IR35 (Ltd Co)
⚠️ Inside IR35 (Umbrella)
Estimates only — assumes standard personal allowance (£12,570), basic/higher rate thresholds 2025/26. No pension contributions, expenses, or accountant savings included. For a precise calculation including your exact circumstances, use the IR35 Guide calculator.
What Is IR35 and Why Does It Matter for Your Rate?
IR35 — formally the Intermediaries Legislation — is UK tax law designed to prevent what HMRC calls "disguised employment". The core question is simple: if you removed the limited company from the picture, would you look and behave like an employee of your client?
If the answer is yes, you're "inside IR35" — and your income from that contract is taxed as employment income, not as business income. That distinction is financially enormous. An outside-IR35 contractor operating efficiently through a limited company might keep 70–75p of every £1 they earn. An inside-IR35 contractor using an umbrella company might keep just 55–62p of every £1 — from exactly the same gross day rate.
You can have some contracts inside IR35 and others outside, simultaneously. Each engagement is assessed independently. A contractor might work two days a week outside IR35 with a small client and three days a week inside IR35 for a large corporation — and needs to manage the tax for each separately.
Inside IR35 vs Outside IR35: The Key Differences
| Factor | Outside IR35 | Inside IR35 |
|---|---|---|
| Taxed as | Business owner (dividends + salary) | Employee (PAYE) |
| Employer NI | Not payable on dividends | ~12.8% deducted before you receive payment |
| Pension | Via company contributions (tax efficient) | Umbrella may offer workplace pension |
| Expenses | Can claim legitimate business expenses | Very limited — no travel to site |
| Typical vehicle | Personal Service Company (Ltd) | Umbrella company or Ltd (taxed as employee) |
| Take-home (£500/day est.) | ~£68,000–£72,000/yr | ~£52,000–£57,000/yr |
| Admin burden | Higher (accounts, corporation tax) | Lower (umbrella handles payroll) |
How Much Extra Should You Charge Inside IR35?
The standard rule of thumb is to add 25–30% to your outside-IR35 rate for an equivalent inside-IR35 engagement. At lower day rates the uplift needed is slightly less; at higher rates where you'd otherwise pay higher-rate dividends, it can exceed 30%.
| Outside IR35 Rate | Equivalent Inside IR35 Rate | Annual Difference |
|---|---|---|
| £300/day | ~£385/day | ~£14,000/yr less take-home if no uplift |
| £400/day | ~£510/day | ~£16,000/yr less take-home if no uplift |
| £500/day | ~£640/day | ~£18,000/yr less take-home if no uplift |
| £600/day | ~£780/day | ~£20,000/yr less take-home if no uplift |
| £700/day | ~£910/day | ~£22,000/yr less take-home if no uplift |
These are estimates. For your specific situation — including whether you draw a salary from your company, your pension contributions, and any legitimate business expenses — use the IR35 Guide for a precise take-home calculation.
How Is IR35 Status Determined?
IR35 status comes down to three key employment tests — drawn from case law and applied by HMRC:
- Control: Does the client control what work you do, how you do it, and when? High client control = inside IR35 risk.
- Substitution: Can you send a substitute to do the work without the client's approval? A genuine right of substitution is the strongest outside-IR35 indicator.
- Mutuality of obligation (MOO): Is the client obliged to offer you work, and are you obliged to accept it? If yes, that suggests employment.
Secondary factors include whether you provide your own equipment, whether you work exclusively for one client, whether you're integrated into the client's team, and how you present yourself to the client's organisation.
This guide covers the rate impact of IR35. For a comprehensive breakdown of how to determine your status, what to include in contracts, and how to work safely both inside and outside IR35, visit ir35guide.co.uk — a dedicated resource for UK contractors navigating IR35.
Who Determines Your IR35 Status?
Since April 2021 (Off-Payroll Working rules), the responsibility for IR35 determination shifted:
- Large and medium private sector clients: The end-client determines status and issues a Status Determination Statement (SDS). You can challenge it but cannot override it.
- Public sector clients: The end-client always determines status — this has been the case since April 2017.
- Small private sector clients: You (through your limited company) still determine your own status. A small company is defined as meeting two of: turnover under £10.2m, balance sheet under £5.1m, fewer than 50 employees.
Calculating Your Rate for IR35 Contracts
First, establish your minimum viable rate using our Freelance Rate Calculator — plug in your income target, expenses, and working hours. That gives you your outside-IR35 floor. Then, for inside-IR35 engagements, apply the 25–30% uplift from that baseline.
Remember: inside IR35 you lose the ability to claim many business expenses. Add an estimate of your normal annual expenses (software, training, equipment) back into your income requirement before calculating the uplift — because you'll need to fund those from net pay rather than pre-tax business revenue.
Frequently Asked Questions
What is IR35 and how does it affect my day rate?
IR35 is UK tax legislation that determines whether a contractor is taxed as an employee or as a self-employed business owner. Inside IR35, income from that contract is subject to PAYE tax and National Insurance, reducing your take-home by roughly 20–30% compared to outside IR35 at the same gross day rate.
How much more should I charge if inside IR35?
Add approximately 25–30% to your outside-IR35 equivalent rate. If you'd normally charge £500/day outside IR35, an inside-IR35 engagement should be quoted at around £625–£650/day to achieve equivalent net income. Use the calculator above for personalised estimates.
Who decides if I'm inside or outside IR35?
For medium and large private sector clients (and all public sector), the end-client makes the determination using a Status Determination Statement. For small private sector clients, you determine your own status. HMRC's CEST tool can help but is not legally definitive.
Can I still operate through a limited company if inside IR35?
Yes, but the income from that contract will be taxed as if you're an employee. Many contractors find it simpler to use an umbrella company for inside-IR35 engagements. The tax treatment is broadly similar; the difference is mainly administrative.