CIS software must verify subcontractor status with HMRC, apply the correct deduction rate (0%, 20%, or 30%), generate monthly return data by the 19th of each month, and issue deduction statements within 14 days. Sage 50 Construction, Xero, QuickBooks, COINS, and Eque2 all handle CIS natively. Sole-trader subcontractors need software that tracks CIS deductions suffered and offsets them against their tax liability. This guide covers both sides of the scheme.
Last reviewed May 2026
The Construction Industry Scheme is one of the longest-standing sector-specific tax compliance regimes in the UK, introduced to address the historical problem of tax evasion in construction subcontracting. Under the scheme, contractors are required to withhold a proportion of payments to subcontractors and pass it directly to HMRC, with the subcontractor recovering the deduction through their tax return or Corporation Tax payment. The scheme affects every UK contractor who engages subcontractors for construction work - from sole-trader builders hiring occasional labour to main contractors managing hundreds of subcontract packages. CIS software automates the verification, deduction, reporting, and statement-issuing obligations that the scheme imposes, reducing the risk of the penalties that apply to every element of non-compliance. This guide covers what CIS software must do for both contractors and subcontractors, and maps the platforms that handle it best.
The Contractor's CIS Obligations: Verify, Deduct, Report, Remit
HMRC's CIS scheme overview sets out four sequential obligations for every contractor. First, before making the first payment to a new subcontractor, the contractor must verify the subcontractor's status with HMRC via the CIS online service or HMRC's API. The verification confirms whether the subcontractor is registered (20% deduction), unregistered (30% deduction), or holds gross payment status (0% deduction). Verification results must be retained and re-checked at the start of each new tax year.
Second, when a subcontract invoice is paid, the contractor must calculate the deduction on the labour element of the payment - materials supplied directly by the subcontractor are excluded from the CIS deduction calculation, as are VAT amounts. Third, by the 19th of each month, the contractor must file a monthly return to HMRC showing all payments made to subcontractors in the previous tax month (6th to 5th) and the deductions withheld. Nil returns must be filed even where no payments were made in the month. Fourth, within 14 days of filing the monthly return, the contractor must issue a payment and deduction statement to each subcontractor paid in the month, showing the gross payment, any materials deduction, and the CIS deduction withheld.
CIS software automates all four steps. At the point of onboarding a new subcontractor, the system prompts for verification via the HMRC CIS API and stores the verification result. When a subcontract invoice is posted, the system applies the correct deduction rate to the labour element and calculates the net payment. At month-end, the system generates the monthly return data for HMRC submission and produces the deduction statements for each subcontractor paid in the period.
The Subcontractor's Side: Tracking Deductions Suffered
Subcontractors who have CIS deductions withheld from their payments can offset those deductions against their own PAYE, NIC, and Corporation Tax liabilities - or claim a repayment if deductions exceed the liability. A sole-trader subcontractor offsets CIS deductions against their Self Assessment income tax and Class 4 NIC liability; a limited company subcontractor offsets them against its monthly PAYE/NIC and employer's NIC remittances to HMRC, with any excess carried forward or repaid.
The subcontractor's accounting software must track every CIS deduction suffered: the contractor's name, the gross payment, the deduction amount, and the tax month in which it was withheld. This data feeds directly into the subcontractor's Self Assessment return (SA103 for sole traders) or the limited company's monthly PAYE reconciliation. Subcontractors who do not track deductions systematically risk either under-claiming (paying more tax than necessary) or over-claiming (creating an HMRC liability if the deduction certificates do not match the contractor's monthly returns). HMRC's guidance on CIS set-off for limited company subcontractors sets out the process for applying deductions suffered against the monthly PAYE remittance.
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Platform Comparison: CIS Software for UK Contractors
| Platform | HMRC Verification | Monthly Return | Deduction Statements | Subcontractor Tracking | Best For |
|---|---|---|---|---|---|
| Sage 50 Construction | API-linked | Native | Auto-generated | Full | SME to mid-size contractors |
| COINS | API-linked | Native | Auto-generated | Full | Large contractors |
| Eque2 | API-linked | Native | Auto-generated | Full | Mid-size UK contractors |
| Xero | Manual verification prompt | Data export | Auto-generated | Basic | Small contractors |
| QuickBooks | Manual verification prompt | Data export | Auto-generated | Basic | Small contractors |
| ConstructEzy | Integrated | Native | Auto-generated | Full | Small to mid UK contractors |
Gross Payment Status: Application, Benefits, and Compliance
Gross payment status allows a subcontractor to receive payments without CIS deduction, improving cashflow significantly - particularly for subcontractors with high turnover whose 20% deductions would otherwise tie up substantial working capital awaiting recovery through Self Assessment or Corporation Tax set-off. To qualify for gross payment status, a subcontractor must pass HMRC's business, turnover, and compliance tests: the business must have been carrying on construction operations for at least 12 months, turnover must exceed prescribed thresholds (currently £30,000 for sole traders and higher for companies with multiple directors), and the tax compliance record must be clean.
HMRC reviews gross payment status annually and can withdraw it if the subcontractor's compliance record deteriorates - for example, if Self Assessment returns are filed late or tax payments are missed. HMRC's gross payment status application guidance sets out the current thresholds and the application process. CIS software for subcontractors should flag when a subcontractor's own gross payment status is at risk of review, based on compliance status data entered by the user or their accountant.
Contractors who pay a subcontractor without deduction on the basis of gross payment status must retain evidence that the status was verified before payment. If HMRC subsequently finds that the status had been withdrawn and the contractor failed to re-verify, the contractor becomes liable for the deductions that should have been withheld. CIS software that prompts annual re-verification for all subcontractors at the start of each tax year (6 April) significantly reduces this risk.
CIS and Making Tax Digital
CIS has its own digital reporting infrastructure via HMRC's Government Gateway, separate from MTD for VAT. Monthly CIS returns are filed electronically via Government Gateway; most CIS-capable accounting platforms file directly through an HMRC API connection rather than requiring the user to log in to Government Gateway manually. MTD for VAT and MTD ITSA are separate obligations that run alongside CIS compliance rather than replacing it.
Sole-trader subcontractors above the MTD ITSA qualifying income threshold must submit quarterly digital updates from April 2026. Their CIS deductions suffered will need to be reflected in the quarterly update and annual reconciliation. The interaction between CIS deductions suffered and the MTD ITSA quarterly submission is an area where accounting software must handle both correctly: the quarterly update reports gross income and expenses; the CIS deduction is a tax credit applied at the annual reconciliation stage rather than a deduction from income within the quarterly update itself. Subcontractors should confirm with their accountant how their chosen MTD ITSA-compatible software handles this interaction before the April 2026 obligation commences.
FAQ
What materials are excluded from the CIS deduction calculation?
CIS deductions apply only to the labour element of a subcontract payment. Materials that the subcontractor has purchased and supplied as part of the works are excluded from the deduction calculation, provided they are separately identified on the invoice. Plant hire costs are generally included in the CIS deduction calculation unless the plant is hired from a third party and the hire cost is passed through at cost without markup. HMRC's CIS guidance provides detailed examples of what constitutes includable and excludable amounts.
What happens if a contractor deducts at the wrong CIS rate?
If a contractor deducts too little - for example, applying a 20% rate to an unregistered subcontractor who should be at 30% - the contractor is liable for the shortfall, not the subcontractor. HMRC will raise an assessment for the underpaid amount, plus interest. If the contractor deducts too much, the subcontractor must reclaim the excess through their Self Assessment return or Corporation Tax computation, which is administratively burdensome but does not create a HMRC liability for the contractor.
Can a subcontractor refuse to accept CIS deductions?
A subcontractor cannot contractually opt out of CIS deductions if they fall within the scheme. The obligation to deduct is the contractor's statutory duty under the Finance Act 2004 and associated CIS regulations; it is not a contractual matter between the parties. A subcontractor who believes they should hold gross payment status but has not yet received it should apply to HMRC; until gross payment status is confirmed, the contractor must deduct at the applicable rate.
How do limited company subcontractors reclaim CIS deductions?
Limited company subcontractors offset CIS deductions suffered against their monthly PAYE and NIC remittances to HMRC. If deductions in the month exceed the PAYE and NIC liability, the excess is carried forward to the following month. If deductions consistently exceed the PAYE liability throughout the year - common for small limited companies with few employees - the company can claim a repayment from HMRC at year-end or apply to offset against Corporation Tax. HMRC's CIS set-off guidance sets out the process and the form required.
Does the CIS scheme apply to overseas subcontractors working in the UK?
Yes. The CIS scheme applies to all construction work carried out in the UK, regardless of the nationality or domicile of the subcontractor. An overseas subcontractor carrying out construction work in the UK must register with HMRC under CIS before receiving payments from a UK contractor. If they fail to register, the contractor must apply the 30% unregistered deduction rate. Double taxation treaty relief may be available to reduce the effective withholding rate for subcontractors resident in treaty countries, but this requires a specific HMRC direction and cannot be applied unilaterally by the contractor.
How We Verified
This article draws on HMRC's Construction Industry Scheme guidance for contractors and subcontractors, HMRC's gross payment status application guidance, HMRC's CIS set-off guidance for limited company subcontractors, the Finance Act 2004, and HMRC's MTD for Income Tax programme documentation. Vendor capability claims reflect publicly available product information as of May 2026. No vendor has paid for inclusion or editorial placement.
