Invoicing in construction has a wrinkle most invoice tools ignore entirely: the Construction Industry Scheme. If you are a subcontractor working for a CIS-registered contractor, they deduct tax from the labour part of your invoice before paying you — 20% if you are verified with HMRC, 30% if you are not — and pass it to HMRC on your behalf. Materials are not deducted. Which means your invoice needs to do something ordinary invoices never do: separate labour from materials clearly, so the contractor can apply the deduction to the right figure.
InvoiceIt's contractor invoice generator is built around exactly that. Mark each line as labour or materials, choose your CIS rate, and the invoice groups the two, shows the deduction against labour only, and gives the contractor a clear amount payable. No spreadsheet gymnastics, no explaining the maths on the phone afterwards.
For CIS purposes, materials are the direct cost of what you actually bought for the job — not a marked-up figure, and not plant you already owned. Contractors are entitled to ask for evidence of material costs, and inflating them is the classic way subcontractors get into bother with HMRC. Put the real cost in, keep the receipts, and the deduction takes care of itself.
Some subcontractors hold gross payment status, meaning no deduction is taken and they settle their own tax. If that is you, set the CIS rate to "not CIS registered" and the invoice shows full totals with no deduction line. The labour and materials split is still worth keeping — main contractors expect it.