Inside vs Outside IR35: What’s the Difference?

For a UK contractor working through a limited company, understanding inside vs outside IR35 helps explain how an engagement is taxed and how much of the contract value ultimately reaches you. This guide explains the practical differences for 2026/27, including working practices, tax treatment and illustrative figures.

If you haven’t yet read the foundational explainer, start with What Is Off-Payroll Working? for the legislative background. This guide assumes that context and goes straight into the financial and contractual detail.

1. The Core Distinction

Outside IR35 means the off-payroll working rules do not apply to the engagement. Where you work through a Personal Service Company (PSC), the company normally invoices the client or agency and remains responsible for its own Corporation Tax and for how profits are extracted. Inside IR35 means the engagement is treated as employment for tax purposes under the off-payroll rules. Where the Chapter 10 rules apply, the deemed employer deducts PAYE Income Tax and employee National Insurance from the deemed direct payment and pays employer National Insurance and, where applicable, the Apprenticeship Levy.

An umbrella arrangement is related but legally different. If you are employed by an umbrella company, HMRC says the off-payroll working rules are unlikely to apply to you because the umbrella is already your employer. In practice, a role advertised as “inside IR35” may lead an agency or client to require the contractor to work through an umbrella company, which is why the two are often discussed together.

The tax label depends on the overall hypothetical direct relationship between the worker and client, not on any single factor. Relevant considerations can include personal service and any genuine right of substitution, the client’s right of control, mutual obligations, financial risk, integration and whether the worker is genuinely operating a business on their own account. The contract terms and the way the engagement works in practice should be considered together.

💡 Action Item: Don’t let a recruiter’s or client’s IR35 “status label” sit unchecked. Request the Status Determination Statement (SDS) in writing before signing, and cross-check it against your actual working practices, not just the contract wording.

2. Inside vs Outside IR35: Side-by-Side Comparison

Factor	Outside IR35 (PSC)	Inside IR35 (Deemed Employment)
Tax Extraction Method	Corporation Tax on company profit, then dividends to you as shareholder	PAYE income tax and employee NI deducted at source by the fee-payer or umbrella
Expense Deductibility	Business expenses (equipment, travel, training, accountancy, insurance) deductible against company profit before tax	Very limited; most home-to-work travel and subsistence are not deductible under current rules
Who handles status and PAYE?	For a medium or large private-sector client, or a public-sector client, the client generally determines status. For a small private-sector client, responsibility for applying the rules normally remains with the worker’s intermediary.	Where the off-payroll rules apply, the deemed employer, often the fee-payer, operates PAYE and employee NI on the deemed direct payment and pays employer NI. Separate PAYE rules apply where the worker is actually employed by an umbrella company.
Equipment & Tools	Company typically owns or leases equipment; capital allowances available	Client typically provides equipment; you have no meaningful capital assets in the engagement
Financial Risk	You bear risk of rework, non-payment, and gaps between contracts	Often less contractual financial risk; payment may be tied more closely to time worked than deliverable outcomes
Client Integration	Engaged as a supplier for a defined outcome; limited integration into internal structures	May be more integrated into team structures, depending on the actual working practices

⚠️ Red Flag: A contract that reads “Outside IR35” but requires you to attend the client’s internal performance review cycle, use a company email signature identical to employees, or report to a named line manager on an ongoing basis, is a contradiction. HMRC’s Check Employment Status for Tax (CEST) tool and any tribunal will weigh actual practice over paperwork.

3. The Take-Home Pay Analysis (2026/27 Scenarios)

The figures below use 2026/27 rates: Corporation Tax at 19% (profits up to £50,000) rising to 25% (above £250,000) with marginal relief in between; employee Class 1 NI at 8% (up to the £50,270 Upper Earnings Limit) and 2% above; employer Class 1 NI at 15% above the £5,000 Secondary Threshold; and dividend tax at 10.75% (basic rate), 35.75% (higher rate), and 39.35% (additional rate), with a £500 dividend allowance.

Both scenarios assume 220 billable days. For the outside-IR35 PSC illustration, the company pays a £12,570 director salary, has £1,500 of annual running costs, and distributes the remaining post-Corporation-Tax profit as dividends. For the umbrella illustration, the assignment rate is reduced by an assumed £1,200 annual umbrella margin, employer NI and the Apprenticeship Levy before gross taxable pay is calculated. Pension contributions, student loans, benefits, VAT and other personal circumstances are excluded. These assumptions are deliberately simplified and the figures are illustrative rather than personalised tax calculations.

Scenario A: £500/day (£110,000 annual contract value)

	Outside IR35 (PSC)	Inside IR35 (Umbrella)
Gross contract value	£110,000	£110,000
Umbrella margin/company running costs	~£1,500 (accountancy, insurance)	~£1,200 (umbrella margin)
Employer NI	~£1,140 (on salary only)	~£13,480 (on nearly full contract value)
Corporation Tax	~£21,370	n/a
Income tax/dividend tax	~£16,770 (dividend tax)	~£25,370 (PAYE)
Employee NI	n/a on dividends	~£3,910
Approximate net take-home	~£69,220	~£65,570

Scenario B: £800/day (£176,000 annual contract value)

	Outside IR35 (PSC)	Inside IR35 (Umbrella)
Gross contract value	£176,000	£176,000
Umbrella margin / company running costs	~£1,500	~£1,200
Employer NI	~£1,140	~£22,050
Corporation Tax	~£38,860	n/a
Income tax / dividend tax	~£40,110 (salary income tax plus dividend tax)	~£54,600 (PAYE, including additional-rate tax)
Employee NI	n/a on dividends	~£5,050
Approximate net take-home	~£94,400	~£92,340

These are illustrative figures based on the stated assumptions, not a substitute for a personalised calculation. At £176,000 of combined salary and dividend income, note that the Personal Allowance tapers to zero above £100,000. This affects both routes and is important to include when comparing the two scenarios.

This inside vs outside IR35 comparison also shows why a headline day rate is not enough to compare two opportunities. The result depends on the engagement structure, the assignment rate, company costs, umbrella deductions and your personal tax position. An inside role offered through an umbrella should therefore be compared using the expected gross taxable pay and net pay, rather than assuming the advertised assignment rate is equivalent to PSC turnover.

💡 Action Item: If you are comparing an outside-IR35 PSC engagement with a role paid through an umbrella, work backwards from the net income you need rather than applying a generic uplift percentage. Ask for the assignment rate and a Key Information Document or pay illustration showing how umbrella margin, employer costs and PAYE deductions affect the amount you would actually receive.

4. The 3 Status Determinants in Practice

Personal Service & Substitution

A genuine right of substitution can point away from employment because it may show that personal service is not required. The weight given to that right depends on the facts, including any restrictions on who can be substituted and whether the right is genuinely capable of being used in practice. A clause that exists only on paper may carry little or no weight in the status assessment.

Control

The client’s right of control over how, when, and where the work is performed is an important status factor. Greater freedom over how services are delivered can point toward self-employment, while a sufficient right of control can point toward employment. Control is significant, but it is not conclusive on its own and must be considered alongside the other status factors.

Mutuality of Obligation (MOO)

Mutuality of obligation is a technical part of employment-status analysis and should not be reduced to whether an engagement has a fixed project end date. At a basic level, there must be sufficient mutual obligations for a contract to exist at all; those basic obligations can be present in both employment and self-employment. The nature of any ongoing obligations, together with the other terms and working practices, forms part of the wider status assessment.

⚠️ Red Flag: The following working practices or contract terms can be relevant indicators of an employment-like relationship. None determines IR35 status by itself, so they should be considered as part of the overall engagement:

• Mandatory attendance at internal staff appraisals or performance reviews
• Fixed core working hours mirroring the employee shift pattern
• A requirement to seek permission before taking holiday, rather than simply notifying availability
• Inclusion in the client’s disciplinary or grievance procedures
• A notice period identical to employee contracts, rather than a fixed-term or deliverable-based exit

5. Recommended Compliance & Protection Stack

Getting the determination right, and being able to evidence it, is one of the most important checks a contractor can make before signing. A practical stack looks like this:

Independent contract and working-practice reviews. A written contract is only part of the picture. If the day-to-day relationship does not match the agreement, the actual working practices can affect the status analysis. Contractors who are uncertain about an engagement can consider obtaining a specialist review of both the contract and the way the work will operate in practice.

IR35 enquiry and liability cover. Some contractors choose specialist insurance designed to help with professional costs arising from an HMRC status enquiry and, depending on the policy, certain tax liabilities. Cover varies significantly, so check the policy wording, exclusions and who is actually insured rather than assuming every IR35 policy provides the same protection.

Accounting records and software. If you operate through a limited company, keeping accurate records for salary, dividends, expenses, VAT where relevant and Corporation Tax is important regardless of IR35 status. Accounting software can make that administration easier, but it does not determine whether an engagement is inside or outside IR35.

If your engagements involve overseas clients or cross-border assignments, IR35 isn’t the only exposure to manage — professional indemnity and health cover gaps are common for contractors working across jurisdictions. See our International IT Consultant Insurance Playbook for how to structure cover alongside your IR35 protection.

6. Operational Hygiene: Keeping Working Practices Consistent

An IR35 determination should continue to reflect the real engagement. If working practices change, the status position may need to be reconsidered. These four practices can help keep the commercial arrangement and the evidence of how it operates consistent:

• Invoice against deliverables, not hours where possible. Milestone-based invoicing (even alongside a day-rate calculation) reinforces that you’re paid for outcomes, not attendance.
• Maintain independent business infrastructure. A separate business bank account, your own equipment where practical, business insurance, and a company website all support the “in business on your own account” test.
• Manage client communications on your terms. Use your own email domain, decline inclusion in the client’s internal org chart or Slack/Teams directory under an employee-style profile, and route contractual queries through your PSC rather than informally through a line manager.
• Avoid org-chart integration. Skip optional internal social events, staff-only training, and appraisal cycles unless they’re genuinely commercial in nature (e.g., a mandatory security briefing tied to the deliverable).

7. Official References

• GOV.UK: Off-Payroll Working (IR35) Guidance
• HMRC: Check Employment Status for Tax (CEST) Tool
• GOV.UK: Rates and Thresholds for Employers

This article is for general information only and does not constitute tax or legal advice. Figures are illustrative and based on 2026/27 rates; consult a qualified contractor accountant for a calculation specific to your circumstances.