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Trade Tax Specialists

CIS guides

CIS and construction tax, explained.

Practical guides on CIS deductions, refunds, gross payment status, VAT reverse charge, expenses and limited company accounting for construction. Written by specialist CIS accountants.

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CIS Basics

16 articles

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CIS Compliance

14 articles

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Software and Tools

8 articles

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CIS Advanced

6 articles

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CIS Refunds

5 articles

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VAT and MTD

4 articles

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Limited Company

2 articles

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Expenses

1 article

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  • Expenses

    Expenses CIS Subcontractors Can Claim: the 2026/27 Guide

    CIS subcontractors overpay tax because deductions are taken at 20% on the labour element of every payment before any expenses are accounted for. Claiming every allowable expense is how most of that overpayment turns into a refund. This guide covers the full construction-specific expense map for 2026/27, including the new 55p mileage rate, tools and PPE, materials, subsistence on site, and the trades-by-trade breakdown.

    14 min read

  • Software and Tools

    Best CIS Accounting Software 2026/27: Complete Guide for Contractors and Subcontractors

    Choosing accounting software as a CIS contractor or subcontractor is not like choosing for any other trade: you need CIS300 direct filing, domestic reverse charge VAT handling and MTD ITSA compatibility, and the differences between products on those three points are significant. This guide compares QuickBooks, Xero, Sage, FreeAgent and Clear Books on the features that matter for CIS work, with current UK pricing verified in June 2026.

    10 min read

  • CIS Basics

    CIS and Mortgages: How Lenders Treat CIS Income and What You Need to Apply

    CIS subcontractors face a specific problem when applying for a mortgage. Most mainstream lenders read net receipts rather than gross CIS earnings, which shrinks the income figure used for affordability by 20% or more before a single expense is claimed. This guide explains how lenders assess CIS income, what documents you need, how your SA302s and Self Assessment returns feed the application, and what you can do to put your best case forward.

    9 min read

  • CIS Compliance

    CIS April 2026 Rule Changes: GPS Revocation, Nil Returns and Director Liability Explained

    Finance Act 2026 reshaped the Construction Industry Scheme from 6 April 2026. HMRC can now revoke gross payment status immediately where a contractor knew or should have known about supply-chain fraud, the reapplication ban after a fraud-grounds removal jumps from 1 year to 5 years, new knowledge-based penalties fall on anyone who pays or makes a return knowing a connected party deliberately failed to comply (FA 2004 s.62A charges 20% of the payment, s.62B recovers 100% of the sum a false return treats as paid), and the CIS300 nil return is mandatory again. This guide explains each change, works the cash-flow and liability numbers in real pounds, and sets out the due-diligence checklist that keeps you on the right side of the new standard.

    14 min read

  • CIS Refunds

    CIS Back Years Tax Refund Guide: How to Claim Up to Four Years of Overpaid Deductions

    Most registered CIS subcontractors overpay tax every year, because the 20% deduction is taken on labour before any expenses or personal allowance are accounted for. HMRC lets you reclaim those overpayments going back four tax years. This guide explains the four-year lookback rule, which years are currently open, the process for unfiled versus amendable returns, the records you need, the claim-by deadlines, the repayment timeline and interest, and works through realistic multi-year examples with real pound figures.

    13 min read

  • CIS Basics

    CIS Registration for Contractors: Step-by-Step Guide 2026/27

    Registering as a CIS contractor is not the same as registering as a subcontractor. The process, the trigger event and the ongoing obligations are all different. This guide covers who must register as a contractor, what you need before you start, the step-by-step HMRC registration process, and the April 2026 due-diligence duties that apply from day one.

    7 min read

  • CIS Compliance

    CIS Deadline Calendar 2026/27: Monthly Returns, SA, MTD and GPS

    Missing a CIS deadline costs money. The penalty for a late monthly return starts at £100 and escalates quickly if left unresolved. This calendar sets out every CIS-related deadline for the 2026/27 tax year: the 12 monthly CIS300 filing dates, the nil return obligation reinstated from April 2026, the Self Assessment filing deadline, MTD quarterly update dates for higher earners, and the GPS review cycle. Every date is based on locked house-position figures from HMRC guidance.

    7 min read

  • CIS Basics

    CIS Deduction Rates: 20%, 30% and Gross Payment Status Explained

    The Construction Industry Scheme operates three deduction rates: 0% for subcontractors with Gross Payment Status, 20% for registered subcontractors, and 30% for unregistered ones. Crucially, the deduction only applies to the labour element of an invoice, not the materials. This guide explains all three rates, shows exactly how the deduction base works with a worked invoice example, and explains why over-deduction across a tax year typically means money back.

    8 min read

  • CIS Basics

    CIS Employment Status: How HMRC Tests Whether You Are Self-Employed or Employed

    CIS does not automatically make a worker self-employed. HMRC applies a three-part employment status test, and getting it wrong exposes a contractor to backdated employer NIC at 15%, PAYE penalties, and the loss of Gross Payment Status. This guide explains the three tests, the CEST tool, the false self-employment risk and what a genuinely self-employed CIS subcontractor looks like.

    7 min read

  • CIS Compliance

    CIS for Contractors: Your Monthly Responsibilities Checklist

    Under CIS a contractor is the withholding agent, responsible for verifying subcontractors, calculating and deducting the right amount, issuing payment and deduction statements within 14 days, filing the CIS300 return by the 19th and paying HMRC by the 22nd every single month. This checklist walks through every step in order, with a worked example across three subcontractors and the full penalty picture for anything missed.

    7 min read

  • CIS Advanced

    CIS for Housebuilders: Managing Multiple Subcontractors and April 2026 Obligations

    Housebuilders sit at the complex end of CIS compliance. They may be mainstream contractors, deemed contractors, or both simultaneously, depending on their activity. They routinely pay 20 to 50 subcontractors each month, face the reinstated nil-return obligation from April 2026, and must now meet a stricter GPS anti-fraud due-diligence standard before each payment. This guide covers the full compliance picture for residential housebuilders in 2026/27.

    8 min read

  • CIS Advanced

    CIS for Labour Agencies: When Your Agency Is a CIS Subcontractor

    A labour agency that supplies workers for construction operations is not always invisible to the Construction Industry Scheme. In many cases the agency itself is treated as the CIS subcontractor, not the individual workers it provides. This creates a set of obligations, and risks, that differ entirely from standard employer-payroll duties. This guide explains when the agency subcontractor rule applies, when it does not, and what agencies must do to stay compliant.

    8 min read