Inside vs Outside IR35: How Your Status Affects Your Take-Home Pay is the comparison every UK contractor runs before signing an engagement. The off-payroll rules, known as IR35, split each contract into two tax worlds: inside, where fees are taxed like employment income, and outside, where fees are taxed through a company as Corporation Tax plus dividend tax. UK contractor take-home pay moves by about £5,000 a year between the two on a £75,000 contract. This guide covers both meanings, the status tests that decide them, a worked comparison on £75,000, and the risks on each side. Every rate cited is from GOV.UK, verified 19 Sep 2026.
What Do Inside and Outside IR35 Mean?
Inside IR35 means the off-payroll rules treat the engagement as deemed employment for tax purposes; outside IR35 means the rules treat it as genuine self-employment. The two meanings produce two different tax charges on identical fees.
Inside IR35 places the tax mechanics with the deemed employer, usually the client or agency paying the personal service company (PSC). The deemed employer deducts Income Tax and employee National Insurance from fees paid to the intermediary, and pays employer National Insurance plus the Apprenticeship Levy where applicable (from GOV.UK, verified 19 Sep 2026). Deemed employers do not deduct student loan or postgraduate loan repayments; the worker repays those through Self Assessment. Umbrella company workers sit apart from this comparison: they are employees of the umbrella, so the off-payroll rules are unlikely to apply to them.
Outside IR35 leaves the tax charge with the company. Fees arrive gross, the company pays Corporation Tax on profits, and the contractor draws salary and dividends. Dividends carry no employee National Insurance and are taxed at the 2026-27 rates: a £500 allowance, then 10.75% basic, 35.75% higher and 39.35% additional (from GOV.UK, verified 19 Sep 2026). Those rates rose from 6 April 2026, the single change most responsible for narrowing the take-home gap.
How Is IR35 Status Decided?
IR35 status is decided by three primary employment status tests applied to each individual contract: control, substitution and mutuality of obligation. The tests mirror employment status case law, not job titles.
- Control asks who decides what work is done, when, where and how.
- Substitution asks whether the PSC can send a substitute, or whether the work requires personal performance by the worker.
- Mutuality asks whether the client is obliged to offer further work and the worker to accept it.
Secondary indicators support the primary tests: financial risk borne by the worker, provision of own equipment, absence of workplace benefits and the stated intention of the parties.
The rules apply contract-by-contract, and a contract is a written, verbal or implied agreement (from GOV.UK, verified 19 Sep 2026). Valid determinations match the written terms to the actual working practices, and HMRC examines both when it checks status. A strong substitution clause fails the test when the client refuses every substitute in practice.
Medium and large clients issue the Status Determination Statement (SDS); small clients leave the determination to the PSC itself. HMRC’s Check Employment Status for Tax (CEST) tool produces a determination but offers no legal safe harbour. Contract reviews by contractor accountants in Newcastle test the written terms against real working practices before either party locks in a status.
How Much Take-Home Pay Difference Is There?
Outside IR35 typically retains more of a £75,000 fee; the take-home difference runs from under £700 a year on a like-for-like rate to about £5,000 once employer National Insurance pressure hits that rate. The IR35 tax difference runs on two engines: National Insurance on the inside route, dividend rates on the outside route.
Inside IR35 sends the fee through deemed employment PAYE. The deemed employer deducts Income Tax at 20%, 40% and 45% against the £12,570 personal allowance, and employee National Insurance at 8% between £12,570 and £50,270 and 2% above. Employer National Insurance adds 15% above £5,000 a year, and clients often recover that cost by cutting the contract rate (from GOV.UK, verified 19 Sep 2026).
Outside IR35 sends the fee to the company gross. Corporation Tax takes 19% on profits up to £50,000, 25% above £250,000 and an effective rate between through marginal relief; our Corporation Tax services page covers that calculation. The contractor draws a small salary through PAYE plus dividends taxed at 10.75%, 35.75% and 39.35% above the £500 allowance. Employer National Insurance applies to the salary only, at 15% above £5,000; single-director companies are generally excluded from the Employment Allowance (from GOV.UK, verified 19 Sep 2026).
The table below runs both models on a £75,000 annual contract fee. The inside model treats the full fee as taxable deemed employment income with the rate intact. The outside model assumes a £12,570 salary, no pension contributions, no other company expenses and all remaining profit drawn as dividends in the same tax year.
| Line | Inside IR35 | Outside IR35 |
|---|---|---|
| Gross fee | £75,000 | £75,000 |
| Income Tax | £17,432 | £0 (salary sits in the allowance) |
| Employee National Insurance | £3,511 | £0 |
| Employer National Insurance | £10,500, paid by the deemed employer | £1,136, on the salary only |
| Corporation Tax | £0 | £12,493 |
| Dividend tax | £0 | £7,967 |
| Personal take-home | £54,057 | £53,404 |
| Share of fee retained | 72.1% | 71.2% |
On a like-for-like rate, inside IR35 edges ahead by £653 in this simple model. The 6 April 2026 dividend rise costs the outside model £966 a year against 2025-26 rates, which closed outside’s historical edge at this fee level.
Employer National Insurance pressure reverses the picture. The deemed employer owes £10,500 on top of the fee, and most clients recover it from the rate: a £75,000 engagement becomes about £65,200 of gross pay, and inside take-home falls to roughly £48,400. Outside then retains around £5,000 more in the year.
Exact figures depend on salary level, pension contributions and expenses, and the comparison runs per contract. Employer pension contributions reduce Corporation Tax outside IR35, and dividend timing across tax years keeps slices in the basic band; our personal tax planning services cover these levers in detail.
What Are the Risks of Getting IR35 Status Wrong?
The main risk of a wrong outside determination is an HMRC assessment for unpaid Income Tax, National Insurance, interest and penalties against the party that holds the liability (from GOV.UK, verified 19 Sep 2026).
HMRC reopens earlier years when it finds a contract inside IR35 after the fact. Since the 2021 reform, liability for medium and large client engagements generally sits with the client or fee-payer rather than the contractor, which is why risk-averse clients default engagements inside. Small-client engagements reverse that protection: the PSC determines its own status and pays the tax owed itself.
Wrongly-inside determinations cost money in the other direction. The contractor overpays tax and reclaims overdeducted amounts through Self Assessment. Tax avoidance schemes promising guaranteed IR35 exits attract HMRC enquiries, and HMRC publishes guidance on recognising them.
Inside IR35 does not switch off company compliance. The PSC still files annual accounts and pays any residual Corporation Tax on income outside the deemed payment (from GOV.UK, verified 19 Sep 2026).
Common Questions Answered
Four short answers cover the points contractors raise most about inside and outside IR35.
Is outside IR35 always better paid than inside?
Outside IR35 usually leaves a higher take-home, but not on every contract. Fees arrive gross, the company pays 19% to 25% Corporation Tax, and the contractor draws salary plus dividends. From 6 April 2026, dividend rates rose to 10.75% basic, 35.75% higher and 39.35% additional, narrowing the gap (from GOV.UK, verified 19 Sep 2026). On short or low-rate contracts, umbrella fees and accountancy costs close the gap further, so the comparison runs per contract.
Can I be inside IR35 on one contract and outside on another?
Yes, the same worker holds inside status on one contract and outside status on another. The off-payroll rules apply contract-by-contract, so each engagement requires its own determination and one SDS never covers a whole portfolio (from GOV.UK, verified 19 Sep 2026).
Who pays the tax if a contract is inside IR35?
The deemed employer pays the tax: it deducts Income Tax and employee National Insurance from fees paid to the intermediary and pays employer National Insurance plus the Apprenticeship Levy where applicable. Student and postgraduate loan repayments stay with the worker through Self Assessment (from GOV.UK, verified 19 Sep 2026).
What is the 5% transitional allowance?
The 5% transitional allowance is a historical deduction that no longer applies. Before the 2017 and 2021 reforms, PSCs inside IR35 deducted 5% of fees before calculating the deemed payment. Where the client or agency is the deemed employer, that deduction is gone, and current planning builds on nothing from it (from GOV.UK, verified 19 Sep 2026).
How Aqua Accounting Can Help
Aqua Accounting runs the inside versus outside comparison before contracts are signed, not after HMRC letters arrive. The firm is an ICAEW Registered Member Firm staffed by ICAEW Chartered Accountants, with 13+ years serving North East businesses from a UK-based team in Newcastle upon Tyne.
Contract reviews test control, substitution and mutuality against real working practices. Company accounts, Corporation Tax, dividend planning and Self Assessment run alongside the determination, whichever way it lands. Inside IR35 engagements keep their residual company filings; outside IR35 engagements keep their salary and dividends strategy.
Bring the draft contract and the rate. Aqua Accounting prices both scenarios line by line, shows the take-home difference on your numbers, and documents the reasoning behind every status call. Inside and outside IR35 is a per-contract question, and contractor take-home pay in the UK deserves its answer before day one.
Disclaimer:
The information provided in this blog is for general informational purposes only and does not constitute professional advice. While every effort is made to ensure accuracy, Aqua Accounting accepts no responsibility for any actions taken based on this content. You should seek professional advice tailored to your individual circumstances.
Omar Ahmed is an ICAEW Chartered Accountant and the Director of Aqua Accounting, a UK-based accountancy practice providing expert accounting and tax services to individuals, sole traders, and small to medium-sized businesses. As a trusted accountant in Newcastle, he offers expertise in annual accounts, self-assessment tax returns, company accounts, VAT, payroll, bookkeeping, and company formation.
With a strong focus on delivering clear and practical financial advice, Omar helps clients stay compliant while improving their understanding of their finances. Through Aqua Accounting, he works closely with business owners to simplify accounting processes, meet tax obligations, and support informed financial decision-making.