A construction subcontractor may complete a job worth thousands of pounds, only to find that the contractor has deducted 30% from the amount eligible for CIS deductions. For small building businesses, electricians, plumbers and other tradespeople, this can create immediate cash flow problems. In many cases, the higher deduction happens because the subcontractor has not registered correctly or HMRC cannot verify their details.
Getting the Construction Industry Scheme explained properly can help you avoid unnecessary deductions, understand your tax responsibilities and recover amounts already paid towards your tax bill. With several CIS changes taking effect in April 2026, contractors also need to review their reporting and compliance procedures.
Key Takeaways
The Construction Industry Scheme (CIS) is an HMRC tax collection system under which contractors deduct money from qualifying payments to subcontractors and pay those deductions to HMRC. The amounts deducted are advance payments towards the subcontractor’s tax and National Insurance liabilities, rather than an additional tax.
The scheme applies to construction operations carried out in the UK and covers many businesses working on building, renovation and infrastructure projects.
For example, a construction company may hire a self-employed electrician to complete electrical installation work. Before paying the electrician, the company checks their CIS status with HMRC and applies the appropriate deduction rate to the qualifying payment.
The arrangement creates separate responsibilities:
Importantly, CIS does not replace Self Assessment, Corporation Tax or PAYE obligations. The correct treatment depends on the subcontractor’s business structure and employment status.
Contractors must register for CIS when they fall within the scheme, while subcontractors should register to avoid the higher deduction rate. A business can operate as both a contractor and subcontractor when it pays other tradespeople and receives payments from another contractor.
A business is generally a mainstream contractor when it carries out construction activities and pays subcontractors for qualifying construction work.
Examples include building companies, construction contractors and certain property developers.
Businesses outside the construction industry may also become deemed contractors if their construction expenditure exceeds £3 million in any rolling 12-month period.
This can affect organisations such as housing associations, large businesses and public-sector bodies. However, some payments made by deemed contractors are exempt, including qualifying work on property used for their own business purposes.
The £3 million test still considers relevant construction expenditure even where particular payments are exempt from CIS reporting.
Subcontractors can include:
Employees are treated differently. If an individual is genuinely employed, the employer must operate the appropriate PAYE arrangements rather than applying CIS simply because the person works on a construction site.
Registration as a subcontractor is not legally compulsory, but remaining unregistered generally results in a higher CIS deduction rate.
CIS covers most construction operations involving buildings, structures and civil engineering works. However, not every service connected with a building project falls within the scheme.
Qualifying activities generally include:
Several activities are normally outside CIS when supplied independently, including architectural and surveying services, carpet fitting, manufacturing and delivering building materials, and scaffolding hire without labour.
A contract containing both qualifying construction activities and other services may require different treatment from a contract covering only excluded work. Contractors should therefore assess the actual contractual arrangement rather than relying solely on a supplier’s job title.
There are also specific exceptions for private householders and certain other payments.
The CIS deduction rates for 2026/27 are 20%, 30% and 0%, depending on the subcontractor’s status confirmed by HMRC.
The 30% deduction is not necessarily a permanent loss. It is an advance payment towards tax and National Insurance, and the subcontractor may receive a refund if their deductions exceed their final liability.
Nevertheless, the difference between 20% and 30% can significantly affect cash flow, particularly for businesses managing wages, equipment and material costs.
Registering correctly, giving contractors matching details and checking verification problems early can help prevent higher deductions on future qualifying payments.
CIS deductions are calculated on the qualifying amount after excluding VAT and certain allowable costs, including qualifying materials purchased directly by the subcontractor. The deduction is not automatically calculated on the full invoice value or the subcontractor’s profit.
Under the HMRC deduction calculation rules, contractors start with the invoice amount and remove qualifying excluded amounts before applying the deduction rate.
Suppose a subcontractor issues an invoice consisting of:
The resulting payments would be:
The difference between the standard and higher rates is £200 on this invoice.
This example assumes the £600 material cost qualifies for exclusion and is supported by appropriate evidence.
Other allowable exclusions can include qualifying plant hire, consumable stores and fuel used for the construction work. Ordinary travelling expenses cannot simply be excluded as materials.
A subcontractor cannot deduct a notional hire charge for equipment they already own. HMRC distinguishes equipment hired from a third party from the subcontractor’s own plant.
Subcontractors can generally avoid the 30% rate by registering for CIS and giving contractors accurate details that HMRC can verify. Successful registration and verification normally allow the contractor to use the standard 20% deduction rate.
Registration is available through HMRC’s online services.
The information required depends on whether the subcontractor operates as a sole trader, partnership or limited company.
For example, a sole trader will normally need their Unique Taxpayer Reference (UTR), National Insurance number and relevant business details.
Contractors use information such as the subcontractor’s UTR and registered business name to verify their status.
Incorrect or mismatched information can prevent successful verification and lead to deductions at the higher rate.
HMRC informs the contractor which rate to apply through the verification process.
Contractors must verify new subcontractors before paying them. Verification is also required for previously used subcontractors if they have not appeared on a CIS return in the current or previous two tax years.
Eligible subcontractors can apply to receive qualifying payments without deductions.
However, gross payment status involves additional turnover, business and compliance requirements.
Gross payment status allows approved subcontractors to receive qualifying construction payments without CIS deductions. Instead of having tax withheld by contractors, they meet their tax obligations through the normal arrangements applicable to their business.
HMRC considers several conditions, including business activity, turnover and compliance history.
The business generally needs to demonstrate that it:
HMRC’s published turnover tests, calculated excluding VAT and materials, include:
Additional rules apply to companies controlled by five people or fewer, including a turnover test based on controlling persons. Eligibility must therefore be assessed against the full HMRC conditions rather than these headline figures alone.
The gross payment compliance test has also included VAT obligations since 6 April 2024. HMRC reviews gross payment status annually, and serious failures may result in withdrawal.
For subcontractors with substantial labour costs or irregular payment schedules, gross payment status can improve working capital. However, receiving payments without CIS deductions does not remove the underlying tax liability.
Contractors must submit CIS monthly returns by the 19th of the month following the relevant tax month. The deductions collected must generally reach HMRC by the 22nd when paid electronically or the 19th when paid by post.
A CIS tax month runs from the 6th of one calendar month to the 5th of the next.
For example, payments made between 6 October and 5 November 2026 must be included in the CIS return due by 19 November 2026.
Contractors must also report payments made to subcontractors who hold gross payment status, even where no deduction has been made.
From 6 April 2026, mainstream contractors must submit a nil return when no subcontractors have been paid during a tax month, unless they have notified HMRC of a period of inactivity.
An inactivity request can cover a period of up to six months.
Deemed contractors have a different legal position. They are not legally required to submit nil returns when no subcontractors have been paid. However, they may receive an automated penalty that HMRC will cancel once they confirm that no relevant payments were made.
Subcontractors can receive credit for CIS deductions already made, but the process differs between sole traders, partnerships and limited companies.
Self-employed subcontractors generally record their gross income and CIS deductions on their self-assessment tax returns.
HMRC calculates the tax liability and credits the deductions already paid. Where deductions exceed the amount due, a refund may be available.
Limited companies must use their payroll reporting arrangements to offset CIS deductions suffered against qualifying PAYE and related liabilities.
The company reports the year-to-date CIS deductions through an Employer Payment Summary (EPS).
If deductions remain unused at the end of the tax year, the company can apply for a refund or have qualifying outstanding tax liabilities settled through HMRC’s process.
Crucially, limited companies must not claim their CIS deductions as a credit directly through the Corporation Tax return. This differs from the treatment for sole traders.
Accurate bookkeeping is particularly valuable here. Missing deduction statements or discrepancies between invoices and payments can complicate claims.
Construction businesses can also read our guide to tax planning for construction companies for broader financial planning considerations.
Three significant changes took effect on 6 April 2026, affecting reporting responsibilities, payments involving public bodies and HMRC’s powers to address fraud.
Mainstream contractors must now submit nil returns for months without subcontractor payments unless they have notified HMRC of inactivity.
This reinforces the need to monitor CIS reporting even during quiet periods.
Certain payments made to local authorities and public bodies acting as subcontractors are now outside CIS.
Contractors do not need to verify those bodies, deduct CIS or report those payments in their CIS monthly returns.
HMRC has expanded powers where businesses make or receive payments, or claim CIS credits, linked to deliberate non-compliance that they knew or should have known about.
Depending on the circumstances, HMRC can:
These fraud penalties are separate from the ordinary 30% CIS deduction rate for unregistered or unverified subcontractors.
The reforms are confirmed measures already in force, not proposals for a future tax year. For more detail on these risks, see our article on CIS fraud rules for UK contractors.
HMRC can impose penalties when contractors fail to submit CIS returns on time or do not comply with their reporting responsibilities.
The ordinary late-filing penalties include:
Additional penalties can apply in more serious cases.
Contractors must also retain CIS records for at least three years after the end of the relevant tax year. HMRC can impose penalties of up to £3,000 where required records cannot be produced.
CIS and the VAT domestic reverse charge are separate requirements that can apply to the same construction transaction.
CIS deals with deductions from qualifying subcontractor payments. The domestic reverse charge determines which VAT-registered business must account for VAT on qualifying construction services.
Where the reverse charge applies, the supplier does not collect the relevant VAT from the customer. Instead, the customer accounts for it through its VAT return.
The reverse charge generally requires consideration of the supplier’s and customer’s VAT status, the type of construction service, CIS reporting and whether an end-user or intermediary exclusion applies.
It does not apply automatically to every CIS transaction. For a detailed explanation, read our guide to the VAT reverse charge for construction services.
Construction businesses can improve CIS compliance by keeping registration, verification, invoicing and tax reporting procedures consistent.
Useful practical measures include:
These controls also support more accurate cash flow forecasts and reduce the need to investigate payment differences at year end.
For businesses reviewing their accounting systems, our article on Making Tax Digital for construction businesses explains related digital record-keeping considerations.
Eligible self-employed individuals should also consider Making Tax Digital for income tax. The rules began applying from 6 April 2026 to those with qualifying income over £50,000, with further scheduled thresholds for subsequent years.
Potentially, yes. CIS deductions taken at the higher rate can still count towards your tax liability. You will need to report the relevant income and deductions through the appropriate tax process and provide supporting evidence where required. Registering for CIS can help avoid higher deductions on future payments.
CIS deductions should not be applied to qualifying material costs that the subcontractor has paid for directly. Contractors may request evidence supporting those costs. The amount available for exclusion depends on the actual transaction and HMRC’s deduction calculation rules.
First, check whether your CIS registration and business details match HMRC’s records. Ask the contractor to review the verification result and identify why the rate was applied. Where an error has occurred, the correction should follow HMRC’s CIS procedures, and you should retain evidence of the deductions already made.
Yes. A CIS-registered subcontractor can provide qualifying construction services to multiple contractors. Each contractor is responsible for applying the correct CIS treatment to its own payments. Subcontractors should retain the payment and deduction statements received from every contractor to support accurate tax reporting.
Private householders paying for construction work on their own homes are generally outside CIS and do not become contractors simply because they hire builders. However, the position can differ when work is commissioned through a business or other organisation already within CIS. The contractual arrangement and nature of the work must be considered.
VAT compliance forms part of HMRC’s gross payment status tests. Minor compliance failures do not automatically lead to withdrawal, but more serious failures can affect eligibility. HMRC also has specific powers to cancel gross payment status immediately in qualifying fraud cases.
At Apex Accountants & Tax Advisors, we provide accounting and tax support for UK construction businesses, including sole traders, subcontractors, building companies and larger contractors.
Our accountants for construction companies provide support with CIS registration, subcontractor verification, deduction calculations, monthly returns, gross payment status applications and construction VAT matters. We also assist with bookkeeping, payroll and financial reporting to help construction businesses maintain accurate records and manage their obligations.
If you are experiencing higher CIS deductions, reporting difficulties or problems reconciling your payments, a review of your current position can help identify the appropriate next steps. Contact us today to discuss your CIS requirements.
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