The required details, VAT, CIS deductions, and the mistakes that get invoices bounced back.
NINO guide · updated 25 September 2026
The quote proposes the work and a price. It does not oblige anyone to pay and it records nothing for tax.
The pro forma sets out what has been agreed, and is often what a customer or a managing agent needs before releasing money. Still not an accounting document, however much it looks like one.
The invoice records the sale, with required contents and a unique reference.
The receipt shows the money arrived. It does not replace the invoice.
Mixing them up causes half the trouble: sending a pro forma while believing you have invoiced means that income is not in your books.
A unique reference and the date. Sequential, no gaps and no duplicates.
Your details. Name or trading name and address — plus your VAT number if you are registered.
The customer's details. Name and address. For a business customer, get it right first time or it comes back.
What you did. A clear description of the work, with quantities where it makes sense.
The money. The net amount, the VAT rate and amount if registered, any CIS deduction, and the total due.
If you are not VAT registered, there is no VAT line anywhere on the document. Adding one is not a formatting choice — it is charging tax you have no right to collect.
If you subcontract for another construction business, the Construction Industry Scheme applies and your customer deducts tax from your payment before it reaches you: 20% if you are registered with HMRC, 30% if you are not. It is not a cost — it counts towards your tax bill — but it is a cash-flow fact you have to plan around.
The detail that saves real money: the deduction applies to the labour element, not to materials. Invoice £1,000 as one lump and the whole £1,000 is exposed. Split it — £400 materials, £600 labour — and only the £600 is. This is the single strongest reason to separate labour and materials on every document you send.
Full explanation, including gross payment status: CIS explained for subcontractors.
Skipping a reference number. Gaps in the sequence are the first thing anyone looks at.
Getting the business customer's details wrong. The invoice bounces back weeks later, unpaid.
Showing VAT when you are not registered. Serious, and easily avoided.
Invoicing one lump sum on a CIS job. You hand over a deduction on your materials for no reason.
Describing it as "sundry works". It loses arguments with customers and with HMRC alike.
This guide is general information, not tax advice. Rules and figures change every year and your situation may differ: check with your accountant or on gov.uk.
Your name or trading name and address, the customer's name and address, a unique reference, the date, a clear description of the work, and the amount due. If you are VAT registered you also need your VAT number, the rate applied and the VAT amount — a VAT invoice has its own required contents.
Yes. You invoice without VAT and you do not show a VAT number or a VAT amount anywhere. Charging VAT when you are not registered is a serious mistake, not a rounding error.
No. A quote proposes the work and a pro forma confirms what was agreed; neither records the sale for tax. Only the invoice does.
A sole trader generally keeps business records for at least five years after the 31 January submission deadline for that tax year. Check the current requirement on gov.uk — and keep the quotes too, not just the invoices.
NINO is a tool for self-employed tradespeople: you build the quote on site, the customer gets a professional PDF over WhatsApp, and customers, appointments and documents stay in one place. You can start free, with no card.
See also: all guides · NINO in your city.