Builders lose weeks of cash flow when a stage invoice does not match what the customer certified. This three-page document sets out the contract, the stage, the cumulative value of work, the retention held, the amounts already paid and the sum due, with every figure traceable to a line.

The sample bills stage 4 of a six-stage house extension for Fallowfield Partners: £90,000 of work to date, £4,500 retention, £60,800 paid before and £29,640 due including VAT. Replace the supplier, contract and stage details first, then check that the table and the final total still add up.