Guide · Invoicing

CIS and domestic reverse charge VAT on electrician invoices, with a worked example

Where the CIS deduction comes off, when you stop adding VAT, what HMRC expects on the invoice, and what each side records on its returns.

Published 13 September 2026 · Certio Software Ltd

CIS in brief

Under the Construction Industry Scheme, a contractor deducts money from a subcontractor's payments and passes it to HMRC as an advance towards the subcontractor's tax and National Insurance. The rate is 20% if you're registered and the contractor can verify you, 30% if you aren't registered or can't be verified, and nothing if you have gross payment status.

CIS covers installing systems such as heating, lighting and power in buildings, but not installing dedicated security systems such as burglar alarms, CCTV and public address systems. Private householders aren't contractors. Give each contractor the exact business name and Unique Taxpayer Reference you registered with, because they verify you with HMRC before paying and a mismatch can mean the higher rate. There are grey areas: HMRC's CIS 340 guide treats repairing or extending an existing system differently from installing one, so check its Appendix A for small jobs.

What the deduction is taken from

The contractor starts from your invoice total and takes off:

  • VAT
  • materials you paid for yourself
  • plant you hired for the job
  • consumables, and fuel other than fuel for travelling
  • the cost of manufacturing or prefabricating materials

The deduction applies to what's left, so in practice it comes off your labour and not your materials. Travelling expenses, including fuel, and subsistence you charge stay in the amount it comes off. If you're VAT registered, materials count at their cost without VAT; if you aren't, include the VAT you paid on them. The contractor can ask for receipts and will estimate the materials if you have none, so list materials as a separate line. They must send you a payment and deduction statement no later than 14 days after each tax month ends.

When the domestic reverse charge applies

Since 1 March 2021, most building and construction services supplied within CIS between VAT-registered businesses have fallen under the VAT domestic reverse charge. HMRC's flowchart for suppliers asks:

  1. Is the work within CIS?
  2. Is it standard or reduced rated?
  3. Is your customer VAT registered?
  4. Is your customer registered for CIS?
  5. Has your customer confirmed in writing that they're an end user?

Yes to the first four and no to the last means the reverse charge applies. Any other answer means normal VAT rules. You only face the question if you're VAT registered yourself.

An end user is a VAT and CIS-registered business that doesn't sell on the construction services it receives. An intermediary supplier is connected to the end user, through a corporate group or an interest in the same land such as landlord and tenant, and passes the work on without changing it. Either can tell you in writing, and you then charge VAT normally.

Householders aren't VAT registered, so you charge them VAT in the usual way. That doesn't make you an end user: if you're the main contractor on a domestic job, VAT-registered subcontractors working for you should still apply the reverse charge if the rest of the conditions apply. Materials you supply as part of the job are reverse charged along with the labour. Labour-only subcontractors are covered, but employment businesses supplying staff aren't.

What the invoice must show

  • Everything a normal VAT invoice needs.
  • A note that the reverse charge applies and the customer must account for the VAT. The VAT Regulations 1995 require a reference to the reverse charge, and HMRC's example wordings include ‘Customer to pay the VAT to HMRC’ and ‘S55A VATA 94 applies’. ‘Reverse charge: customer to pay the VAT to HMRC’ does both jobs.
  • The amount of VAT due under the reverse charge, or the rate if you can't show the amount, without adding it to the total.

Worked example

You're a VAT-registered electrician, registered for CIS at 20%. A VAT and CIS-registered contractor refitting a shop asks you to rewire it and hasn't given you an end user notice. Your labour is £1,800 and the materials you bought cost £700 before VAT.

Invoice and paymentAmount
Labour: rewire of shop unit£1,800.00
Materials supplied£700.00
Net total£2,500.00
VAT at 20%, shown but not charged. ‘Reverse charge: customer to pay the VAT to HMRC’£500.00
Invoice total£2,500.00
CIS deduction the contractor makes: 20% of £1,800 labour−£360.00
Payment you receive£2,140.00

Your returns. Include £2,500 in box 6 of your VAT Return, with no output VAT for this sale. The £360 appears on the contractor's statement and counts towards your tax: sole traders claim it on their Self Assessment return, and limited companies through their payroll submissions to HMRC.

The contractor's returns. They add £500 to box 1, reclaim £500 in box 4 under the normal rules and include £2,500 in box 7. Their CIS monthly return shows a payment of £2,500, materials of £700 and a deduction of £360, which they pay to HMRC.

If the customer were an end user who had told you so in writing, you would charge VAT normally: £2,500 plus £500 VAT makes £3,000. The CIS deduction stays at £360, because it ignores VAT and materials, so you would receive £2,640.

Watch out for

  • Reverse charge supplies can't go through the Cash Accounting Scheme, and Flat Rate Scheme users leave them out of their flat rate calculation.
  • With no VAT coming in on reverse charge work, you may end up reclaiming more than you pay. HMRC lets you apply to move to monthly returns.
  • Don't split labour and materials into separate invoices or linked contracts to keep materials out of the reverse charge.
  • If a customer's status changes during a contract, they must tell you, and the VAT treatment changes from that point.
Straight answers

Questions

Does the CIS deduction come off materials?
Not off materials you bought yourself for the job. The contractor takes off VAT, those materials, hired plant, consumables, fuel other than for travelling and prefabrication costs, then applies the deduction to what's left.
Do I use the reverse charge for a householder?
No. Householders aren't VAT registered, so you charge VAT in the normal way. Among other conditions, the reverse charge needs a customer registered for both VAT and CIS that hasn't told you in writing it is an end user or intermediary supplier.
What wording does a reverse charge invoice need?
It must make clear that the reverse charge applies and that the customer accounts for the VAT. HMRC's example wordings include ‘Customer to pay the VAT to HMRC’ and ‘S55A VATA 94 applies’, and ‘Reverse charge: customer to pay the VAT to HMRC’ also names the reverse charge. Show the VAT amount or rate without adding it to the total.
I'm not VAT registered. Does any of this apply?
The reverse charge doesn't, because you don't charge VAT. CIS still does, and when the deduction is worked out your materials count including the VAT you paid on them.
Can I use the Flat Rate Scheme with reverse charge work?
Reverse charge sales are left out of your flat rate calculation. HMRC suggests checking whether the scheme still suits you, because on it you can't reclaim the VAT you pay on materials and overheads.
Invoicing for electricians

CIS and reverse charge wording built in

Certio invoices apply CIS to labour only, never to materials, and carry the domestic reverse charge wording, with card payment links and chasing for unpaid invoices. The same app produces EICR, EIC, Minor Works and PAT certificates, and priced quotes from a drawing.

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