Reverse charge VAT on construction invoices: worked examples and the mistakes that cost you

A subcontractor finishes a first-fix electrical package and invoices £5,000 for the work. Under standard VAT rules the invoice total would be £6,000 - £5,000 net plus £1,000 VAT that the subcontractor collects and pays to HMRC. Under the domestic reverse charge, the invoice total stays at £5,000. The subcontractor still states VAT at 20% and the notional £1,000 figure, but the note reads "Reverse charge: customer to account for VAT of £1,000 to HMRC." The contractor - not the subcontractor - declares and recovers that VAT in their own return. The charge applies whenever three conditions are all met: both businesses are VAT-registered, the work falls within Construction Industry Scheme (CIS) scope, and the contractor has not given written confirmation that they are the end user of the services.

When the Reverse Charge Applies - and When It Does Not

The domestic reverse charge covers most CIS-scope work between VAT-registered businesses: building, alteration, repair, extension, demolition, scaffolding, site clearance, drainage, and the installation of heating, lighting, electrical, plumbing, and water systems. Painting and decorating are also in scope. What sits outside the reverse charge are professional services supplied on their own - architecture, surveying, consulting - materials-only deliveries, and employment businesses that supply staff rather than carry out the construction work themselves.

The end-user exception is where businesses most often get caught out. A property developer who retains and manages a building can notify their sub-contractor in writing that they are the end user, at which point the sub-contractor reverts to charging VAT normally. The key word is writing: if you believe your customer is the end user but have no written confirmation, HMRC expects you to apply the reverse charge regardless. Verbal assurances are not enough, and subcontractors who charge VAT on the basis of an informal conversation can find themselves assessed for output tax they did not properly declare.

What the Invoice Must Show

The most common template error is treating "reverse charge" as an instruction to remove VAT from the invoice entirely. It is not. HMRC requires the invoice to show all standard VAT invoice information, state that the reverse charge applies, and disclose either the VAT amount or the VAT rate. The amount payable to the subcontractor excludes VAT - but the VAT figure must be visible.

Two invoice formats for the same job:

Standard VAT invoice (not reverse charge):

• Labour: £3,000
• Materials: £1,000
• Net total: £4,000
• VAT at 20%: £800
• Invoice total: £4,800

Reverse charge invoice (same job, B2B CIS scope):

• Labour: £3,000
• Materials: £1,000
• Net total: £4,000
• VAT at 20% (reverse charge): £800
• Amount payable: £4,000
• Required note: "Reverse charge applies. Customer to account for VAT of £800 to HMRC. VAT Act 1994 Section 55A."

The subcontractor records £4,000 in Box 6 of their VAT return and nothing in Box 1. The contractor records £800 in Box 1 (output tax) and £800 in Box 4 (input tax reclaim, subject to their normal VAT position), and £4,000 in Box 7. For a fully taxable contractor the net cash effect is nil - the entries cancel - but the reporting must still be done correctly.

CIS Deductions Running Alongside the Reverse Charge

CIS and the domestic reverse charge run in parallel and the calculations are independent. CIS is deducted from the labour portion of the net invoice only - it does not apply to materials and it has nothing to do with the VAT position.

Building the same job through to what the contractor actually pays:

• Labour: £3,000
• Materials: £1,000
• Net total: £4,000
• VAT at 20% reverse charge (customer to account for): £800
• Amount payable before CIS deduction: £4,000
• CIS deduction at 20% on labour (£3,000 x 20%): £600
• Amount contractor pays subcontractor: £3,400

The subcontractor receives £3,400 in cash. The contractor holds back £600 as a CIS deduction and pays it to HMRC on behalf of the subcontractor. The £800 VAT is handled entirely within the contractor's VAT return - it never moves as a cash payment between the two businesses.

Invoicing templates that were built before March 2021 typically place VAT on the total amount due and have no CIS deduction field. A sub-contractor using one of those templates for a reverse-charge job will either add VAT to the invoice total - which is wrong - or remove the VAT line entirely and omit the required disclosure. Either way the invoice is non-compliant before it reaches the contractor's accounts department. The Invoices feature in Zigaflow supports both CIS deduction lines and the reverse-charge VAT declaration in the same document template, so the sub-contractor generates the right layout without manually editing line items on every invoice.

Three Mistakes That Get Flagged

Charging VAT when the reverse charge applies. A subcontractor adds 20% VAT to an invoice that should be reverse-charge. The contractor pays it, and the subcontractor includes it in Box 1 of their return. HMRC can assess the output tax from the subcontractor even if the contractor also paid it in good faith. From April 2026, HMRC has powers to cancel a construction firm's Gross Payment Status where they are linked to non-compliant invoicing arrangements. The financial exposure is doubled: the subcontractor owes the output tax, and the contractor loses input tax credit on a wrongly-charged invoice.

Splitting labour and materials onto separate invoices. Some businesses try to issue a labour-only invoice under the reverse charge, then a separate materials invoice charging VAT normally, on the theory that materials are out of scope. HMRC's position is explicit: where materials are supplied together with CIS construction services as part of a single contract, the reverse charge applies to the full order value. Issuing split invoices for what is commercially a single supply does not change the VAT treatment.

Omitting the VAT amount from the invoice. The required wording alone - "customer to account for VAT to HMRC" - is not sufficient without the VAT rate or amount. Invoices that carry the phrase but omit both the rate and the figure are non-compliant. HMRC describes inaccuracy penalties ranging from 0-30% of the unpaid VAT for lack of reasonable care, up to 30-100% for deliberate and concealed errors.

The domestic reverse charge is ultimately an invoicing compliance issue, not a tax return problem. The return entries flow correctly only when the invoice is correct first: the right amount payable, the right disclosure wording, CIS calculated on labour only. Businesses that have never updated their invoice templates since the rule came into force in March 2021 are filing returns that may look internally consistent but are built on documents HMRC can challenge line by line. The fix is not a change to how you file - it is a change to what your document templates generate. For more on the wider Construction Industry Scheme rules, see the glossary. The construction and trade page covers the broader operational context for sub-contractors and main contractors across the sector.

Sources

• CIS and VAT: How They Work Together for SubcontractorsFinistry · accessed 2026-09-29
• VAT Reverse Charge for Construction Services Explained (2026 Guide UK)Baywood Accounting · accessed 2026-09-29
• VAT reverse charge for building and construction servicesAMS Accountancy · accessed 2026-09-29
• HMRC Steps Up Pressure on VAT Reverse Charge in the Construction IndustryApex Accountants · accessed 2026-09-29
• VAT Rules for Construction: Zero-Rate, Reverse Charge, and Avoiding HMRC PenaltiesArmstrong Watson · accessed 2026-09-29