Construction Industry Scheme
Understand contractor and subcontractor status, verification, deductions, monthly returns and records.
Construction Industry Scheme explained
The Construction Industry Scheme sets rules for payments by construction contractors to subcontractors. Contractors must determine whether CIS applies, verify subcontractors where required, apply the correct deduction treatment, report payments and give deduction statements.
This learning path covers UK rules and ReturnDeck’s UK form set. Check the effective period and official source before using a rule for a live filing.
Learn it in stages
Beginner · Who is a contractor or subcontractor?
Learn the CIS roles and the types of construction work within the scheme. A business can be both contractor and subcontractor. Status under CIS does not by itself decide employment status.
Intermediate · Verification and deductions
Before paying a new subcontractor, contractors may need to verify them with HMRC. The verification result determines whether payment is made gross or with the applicable CIS deduction rate. Calculate deductions from the correct payment base rather than automatically applying a percentage to the full invoice.
Advanced · Monthly returns and statements
Contractors report subcontractor payments and deductions on monthly CIS returns, maintain supporting records and provide payment/deduction statements. Nil-return and correction rules should be understood where relevant.
Subcontractor · Using CIS deductions
A subcontractor records gross income and CIS deductions suffered. Those deductions are credits toward the relevant tax liabilities; they are not a substitute for recording the underlying income and expenses correctly.
Example: subcontractor invoice
A verified subcontractor invoices for labour and separately identified materials. Determine which elements form the CIS deduction base, apply the verification result, record the gross payment and deduction, issue the statement and include the payment on the contractor’s monthly return. The subcontractor then records the same income and deduction in its own tax records.
Apply this in Practice Mode →Common mistakes to avoid
- Applying CIS to work outside the scheme without checking scope
- Deducting from the whole invoice without considering excluded elements
- Treating CIS verification as an employment-status test
- Missing monthly returns or deduction statements
- Recording only the net cash received in the subcontractor’s accounts
Records and preparation checklist
Before calculating or filing, assemble the evidence that supports the position. This makes the return easier to complete and easier to explain later.
- Contractor/subcontractor role and work scope
- Subcontractor verification result
- Invoice split and deduction calculation
- Monthly return record
- Payment and deduction statement
- Subcontractor accounting for gross income and CIS suffered
Key terms
A business that pays subcontractors for construction work and is within CIS.
A business carrying out construction work for a contractor.
HMRC process used to determine the subcontractor’s CIS payment status.
Tax deducted by a contractor from qualifying subcontractor payments and paid to HMRC.
Follow the lesson into the form
ReturnDeck’s 1,139 mapped UK fields connect form codes to plain-English meaning, applicability, source figures, calculation notes, examples, common mistakes, interactions and HMRC sources.
Calculate and check
Use the related ReturnDeck calculator or checker to turn the lesson into a practical result where the verified rules support deterministic calculation.
Open related tool →Practice what you learned
Move from learning into a fictional case file, source documents, return completion, validation and a worked answer. Practice Mode never submits anything to HMRC.
Continue to practice →Official HMRC / GOV.UK sources
These are the primary official sources for this learning path. ReturnDeck summarises them for learning; the official material remains the authority.
Source set reviewed for ReturnDeck’s 2026 UK learning layer. Tax rules change; verify the effective date for a live decision.