Plain English definitions

CIS and construction tax glossary

50 definitions of the terms UK construction subcontractors and contractors actually need to understand. Written by specialist CIS accountants. All figures verified for 2025/26.

CIS and construction tax glossary

CIS fundamentals

Construction Industry Scheme (CIS)

Contractor

Subcontractor

Deemed contractor

Construction operations

CIS registration

UTR (Unique Taxpayer Reference)

HMRC CIS online service

Deductions and rates

CIS deduction

Deduction rates (0%, 20%, 30%)

Labour-only deduction base

Materials deduction

Verification number

Payment and deduction statement

Allowable Expenses (CIS)

AMAP Mileage Rates

Class 4 National Insurance

CITB Levy

Returns and compliance

CIS300 Monthly Return

Nil Return

Pre-notification of Inactivity

Regulation 24ZA (Public Sector Exemption)

Late Filing Penalties (CIS)

Compliance Test

Turnover Test

Business Test

Due Diligence (April 2026)

Knew or Should Have Known Standard

Section 62A Penalty

Section 62B Penalty

Five-Year Reapplication Ban

Verification (Subcontractor)

Employment Status

Retention Payments

EPS (Employer Payment Summary)

Refunds and repayments

CIS Refund

Over-deduction

Overpayment Relief

SA302 / Tax Calculation

Corporation Tax Offset (CIS)

In-Year Repayment (EPS Route)

Business structures

Gross Payment Status (GPS)

Sole trader

Limited company subcontractor

VAT and MTD

VAT Domestic Reverse Charge (DRC)

End User (DRC)

Flat Rate Scheme and CIS

Making Tax Digital for Income Tax (MTD ITSA)

Quarterly Updates (MTD)

Bridging Software