Outside IR35 To Inside Overnight: The Financial Damage Of A Reclassified Contract
Outside IR35 to Inside Overnight: The Financial Damage of a Reclassified Contract
When a contract is reclassified from outside IR35 to inside IR35, either through an HMRC challenge or a client's own reassessment, the fee-payer becomes liable for Income Tax and employee National Insurance on the deemed payment through PAYE, plus employer National Insurance at 15% on earnings above £5,000 for 2026/27, and potentially the Apprenticeship Levy. HMRC's own guidance on the off-payroll working rules sets out how status is determined under Chapter 10 of the Income Tax (Earnings and Pensions) Act 2003, and since 6 April 2024 a set-off mechanism reduces the risk of the same income being taxed twice, but it does not remove the cost entirely, and understanding exactly what it does and does not cover is essential before assuming the financial exposure of a reclassification is smaller than it actually is.
I have worked through the numbers on reclassified contracts often enough to know that the headline figure people fear, the full PAYE bill on the contract value, is rarely the whole story anymore. The 2024 offset genuinely changed the picture. But it did not change it as much as some of the more optimistic commentary at the time suggested, and the gap between what people expect the offset to cover and what it actually covers is where the real financial surprise tends to land.
Who Determines Status, and Who Actually Pays
Under the off-payroll working rules, a medium or large private sector client engaging a contractor through a personal service company (PSC) is responsible for determining whether the engagement would be one of employment if the contractor were engaged directly. If the determination is "inside IR35", the fee-payer, usually the recruitment agency in the supply chain, or the end client directly where there is no agency, must operate PAYE on payments made to the PSC, deducting Income Tax and employee National Insurance before the money reaches the contractor, and separately accounting for employer National Insurance and any Apprenticeship Levy due.
A reclassification happens in one of two ways. Either HMRC challenges an "outside" determination during a compliance check and concludes it should have been "inside", or the client itself reassesses the role, perhaps following internal review or a change in working practices, and moves the contractor from outside to inside going forward. The first scenario carries the sharper financial sting, because it applies retrospectively to income already paid without PAYE having been operated at the time.
What a Reclassification Actually Costs
When HMRC successfully challenges a status determination, the deemed employer becomes liable for the tax that should have been deducted under PAYE, calculated by grossing up the payments made to the PSC as if they were employment income. This includes basic rate, higher rate, or additional rate Income Tax depending on the contractor's total income, employee National Insurance, employer National Insurance at 15% on earnings above the secondary threshold of £5,000 for 2026/27, and, where the deemed employer's total pay bill across connected entities exceeds £3 million a year, the Apprenticeship Levy at 0.5% on that excess. Interest accrues on the underpaid tax from the original due date, and penalties may apply depending on whether HMRC considers the original determination careless, deliberate, or made with reasonable care.
What this Widget is About: This interactive explainer from My Tax Accountant breaks down the true financial exposure of a contract reclassified from outside to inside IR35 under the off-payroll working rules. By adjusting your contract value, penalty level, and regional tax bands, you can instantly see how the April 2024 double-taxation offset shields you from gross PAYE bills, while uncovering the residual employer National Insurance and levy liabilities that remain strictly non-offsettable. Simply tailor the contract parameters in the dynamic calculator or test your client against the updated 2026/27 small company exemption thresholds below to evaluate your net financial exposure in real time.
A Worked Example: The Scale of the Exposure
Take a contractor engaged at £550 a day for 220 working days across a tax year, a contract value of £121,000, determined outside IR35 at the time but later found by HMRC to have been inside. Grossing this up as deemed employment income, and assuming the contractor has no other income affecting their tax band, the Income Tax and employee National Insurance that should have been deducted at source come to a substantial proportion of the contract value once higher rate tax is factored in on the portion above the higher rate threshold. Separately, employer National Insurance is charged on the deemed payment above £5,000 at 15%, which alone can add well over £15,000 to the bill on a contract of this size, before any Apprenticeship Levy, interest, or penalty is added. This is the figure that made businesses nervous about engaging PSC contractors at all in the years immediately following the 2021 private sector reforms, and it is the figure the 2024 offset was specifically designed to soften, though not eliminate.
The 2024 Offset: What It Actually Covers
Since 6 April 2024, a set-off mechanism allows HMRC to reduce the deemed employer's PAYE liability by the tax and National Insurance the contractor and their PSC have already paid on the same income. This directly addresses the double taxation problem that existed before, where the deemed employer could be charged the full PAYE liability without any credit for Corporation Tax the PSC had already paid, Income Tax and employee National Insurance the contractor had already paid on a salary drawn from the company, or Income Tax the contractor had already paid on dividends funded by that same income.
The offset covers Corporation Tax paid by the PSC on the relevant income, Income Tax and employee National Insurance on any salary the contractor drew from the PSC funded by that income, Class 2 and Class 4 National Insurance where relevant, and Income Tax paid on dividends the contractor received from company profits generated by the assignment. What it explicitly does not cover is any employer National Insurance the PSC itself may have paid, and it never covers the employer National Insurance now due from the deemed employer on the reclassified payment, since that liability did not exist under the original outside-IR35 arrangement and cannot be offset against tax the contractor never paid. The Apprenticeship Levy is similarly excluded from the offset entirely.
Why the Offset Doesn't Make the Bill Disappear
This is the detail that surprises deemed employers who assume the 2024 change resolved the financial exposure of a reclassification. It substantially reduces double taxation on the income tax and employee National Insurance elements, since those amounts genuinely were paid once already, just by the wrong party through the wrong mechanism. But the employer National Insurance charge is new money that was never paid under the outside-IR35 structure, because a PSC engaged as a genuine business supplier does not pay employer National Insurance on its own trading income the way an employer does on a salary. A rough industry rule of thumb puts the residual cost of a successful HMRC challenge, after the offset is applied, at somewhere around 10% to 15% of the contract value, driven almost entirely by employer National Insurance, interest, and any penalty, rather than by the income tax element that the offset now largely neutralises.
The offset also requires HMRC to be able to identify the worker and the intermediary, confirm that returns have been submitted, and establish that the relevant tax was actually paid or assessed, and where HMRC cannot calculate an accurate figure, it applies a best estimate rather than the exact amount. The mechanism also applies to deemed direct payments made on or after 6 April 2017 where the trigger event, such as a Regulation 80 determination becoming final, occurs on or after 6 April 2024, so older cases are not automatically excluded, but the deemed employer still needs to actively engage with HMRC to secure the set-off rather than assuming it applies automatically.
Reasonable Care and the Penalty Question
Whether penalties apply on top of the tax, interest, and employer National Insurance depends heavily on whether the original determination was made with reasonable care. A client using HMRC's Check Employment Status for Tax (CEST) tool, or an equivalent properly reasoned assessment, documenting the specific factors considered, control, substitution, mutuality of obligation, and reviewing the determination periodically as working practices evolve, is in a considerably stronger position than one that issued a blanket "outside IR35" determination across an entire contractor population without individual assessment. HMRC's approach to penalties distinguishes between careless errors, which attract a lower penalty band, and deliberate non-compliance, which does not. A client who can demonstrate a genuine, documented process, even where HMRC ultimately disagrees with the conclusion reached, is far less likely to face a penalty on top of the tax and interest than one who cannot show any real assessment took place.
The Small Company Exemption: A Genuinely Live Issue for 2026/27
This is worth flagging specifically for the current tax year, because it changes who is even responsible for making the determination in the first place. Small companies, as defined under the Companies Act 2006, are exempt from the off-payroll working rules entirely, meaning responsibility for determining IR35 status reverts to the contractor's own intermediary under the older Chapter 8 rules. Following changes to company size thresholds that took effect for financial years beginning on or after 6 April 2025, a company now qualifies as small if it meets at least two of three tests: annual turnover of no more than £15 million, a balance sheet total of no more than £7.5 million, and no more than 50 employees on average.
Because a company's size for off-payroll purposes is judged against its previous financial year, the practical effect of these higher thresholds first lands for many businesses from 6 April 2026, when an estimated 14,000 companies previously classed as medium-sized reclassify as small. For a contractor working with one of these newly reclassified clients, the responsibility for determining their own IR35 status shifts back to their own PSC from that point, which is a meaningful change in exposure and process, entirely separate from any reassessment of the actual working arrangement itself. Contractors should ask their end client directly, or through their agency, whether the client's size classification has changed for 2026/27, since this determines who now carries the compliance burden, and it is easy to miss amid the more commonly discussed status-review triggers.
What this Widget is About: This interactive explainer helps UK taxpayers and contractors understand the real financial impact when a contract is reclassified from outside IR35 to inside IR35, including who is liable, what the 2024 offset actually covers, and why employer National Insurance remains a significant residual cost. Use the tabs at the top to move between an overview, details of who determines status and pays, a clear breakdown of the costs, an explanation of the offset rules, a simple residual-cost calculator, and practical steps to take if reclassification occurs. Enter your day rate and working days in the calculator to see an illustrative estimate of the main uncapped exposure after the offset is applied. The widget is designed for easy use on any device and reflects current 2026/27 rates and HMRC guidance.
Practical Financial Steps If Your Contract Is Reclassified
● Request a clear breakdown from the deemed employer of how the liability was calculated, specifically confirming whether the 2024 offset has been applied and what evidence was used to establish the amount already paid by your PSC.
● Keep detailed, contemporaneous records of Corporation Tax paid, salary and dividends drawn from the relevant contract income, and personal tax paid on those amounts, since this evidence is what supports a set-off claim.
● If you disagree with a reclassification, use the client's status disagreement process before the position becomes final, since correcting an incorrect determination early avoids the retrospective liability building up in the first place.
● Review your company's cash position for the ongoing tax year if a contract moves from outside to inside prospectively, since PAYE will now be deducted at source, materially changing your PSC's monthly cash flow and dividend planning.
● Confirm your end client's small company status for 2026/27 specifically, given the higher thresholds now in effect, since this may shift responsibility for your IR35 status back to you.
Scotland and Wales: No Separate Off-Payroll Regime
The off-payroll working rules, the set-off mechanism, and the small company exemption apply identically across the whole of the UK, since IR35 and the underlying Income Tax and National Insurance framework are reserved matters administered by HMRC. Where a reclassified contractor is a Scottish taxpayer, the Income Tax element of any PAYE liability due on the deemed payment is calculated using Scottish Income Tax rates and bands rather than the rest of the UK's rates, since PAYE operates according to the contractor's tax residence in the normal way. Employer and employee National Insurance are unaffected by this distinction and remain identical across all four nations. Wales follows the same UK-wide rates as England, having not diverged under its devolved powers to date.
Key Takeaways
A reclassified contract is genuinely less financially catastrophic than it was before April 2024, because the offset mechanism removes the worst of the double taxation that previously made a successful HMRC challenge disproportionately expensive. But it is not free, and employer National Insurance in particular remains a real, uncapped cost that the offset was never designed to touch. Anyone engaging or working through a PSC arrangement in 2026/27 should understand precisely where that line sits, rather than assuming either that reclassification is now a minor administrative correction, or that it still carries the full, uncapped exposure it did before the 2024 reform.
FAQs
Who is liable for the tax if my outside IR35 contract is reclassified as inside?
The deemed employer, usually the recruitment agency in the supply chain or the end client where there is no agency, becomes liable for the PAYE, employee and employer National Insurance, and any Apprenticeship Levy due on the reclassified payments, not the contractor personally.
Does the 2024 offset mean I won't be charged twice if my status is reclassified?
The offset significantly reduces double taxation on Income Tax, employee National Insurance, Corporation Tax already paid by your company, and tax already paid on salary and dividends funded by the relevant income, but it does not cover employer National Insurance or the Apprenticeship Levy, which remain a real additional cost to the deemed employer.
How much does a reclassification actually cost after the offset is applied?
As a rough industry estimate, the residual cost after the offset tends to fall somewhere around 10% to 15% of the contract value, driven mainly by employer National Insurance at 15%, interest on the underpaid amount, and any penalty, rather than the income tax element, which the offset largely neutralises.
What is the current employer National Insurance rate for a reclassified contract in 2026/27?
Employer National Insurance is charged at 15% on earnings above the secondary threshold of £5,000 per year for 2026/27, a rate and threshold that have applied since 6 April 2025 and remain unchanged for the current tax year.
What is the small company exemption and does it affect me?
Small companies, as defined under the Companies Act 2006, are exempt from the off-payroll working rules entirely, meaning the contractor's own intermediary determines IR35 status instead. Following higher thresholds effective from 6 April 2025, around 14,000 previously medium-sized companies reclassify as small from 6 April 2026, shifting this responsibility back to affected contractors.
Can I dispute a status determination before it becomes final?
Yes. Clients are required to operate a status disagreement process, and raising concerns through this route before a determination becomes final is considerably more effective than challenging a reclassification after PAYE has already been backdated and applied.
Does a genuine, documented status assessment protect the deemed employer from penalties?
It can. HMRC distinguishes between careless and deliberate non-compliance when calculating penalties, and a client who used a proper assessment process, such as HMRC's Check Employment Status for Tax tool with individual reasoning documented, is in a considerably stronger position than one that applied a blanket determination without genuine assessment.
About the Author
Maz Zaheer, AFA, MAAT, MBA, is the CEO and Chief Accountant of MTA and Total Tax Accountants, two premier UK tax advisory firms. With over 15 years of expertise in UK taxation, Maz provides authoritative guidance to individuals, SMEs, and corporations on complex tax issues. As a Tax Accountant and an accomplished tax writer, he is renowned for breaking down intricate tax concepts into clear, accessible content. His insights equip UK taxpayers with the knowledge and confidence to manage their financial obligations effectively.
Disclaimer:
This article explains the general position for the 2026/27 tax year and is accurate at the date of publication. Tax outcomes depend on individual circumstances, and rules change. It is not advice for your situation. For guidance on your own position, speak to a qualified accountant or tax adviser. My Tax Accountant accepts no liability for action taken solely on the basis of this article.
