Finance - Managing a Project Stage Payment Schedule

Agree the number of milestones, the percentage tied to each, and the specific completion event that triggers each invoice. Confirm in the order confirmation or contract before work begins.

Log each milestone with its trigger event, expected date, and invoice amount against the job. Ensure both your team and the customer have a copy.

Raise and send the deposit invoice the same day the contract is signed. Hold work until the deposit clears unless written credit terms apply.

When a defined milestone event is completed, raise the corresponding stage invoice within one business day. Do not wait for a monthly billing cycle.

Review the job record before raising the final invoice. Record every variation approved in writing as a line item. Unrecorded variations are the most common cause of final payment disputes.

Raise the final invoice on the day the completion event is met. Deduct deposits and previous stage payments as explicit line items. Sync to Xero, QuickBooks, or FreeAgent the same day.

Stage invoices are raised days or weeks after the trigger milestone, giving customers free credit and creating unnecessary cash flow gaps between project completion and payment receipt.

The final invoice arrives as a surprise to the customer because the stage schedule was not written into the original contract, leading to disputes that delay the last and largest payment.

Approved variations completed during the project are not captured before the final invoice is raised, so they either appear as unexpected additions or are written off entirely.

What is a typical stage payment structure for a construction or installation project?

A common four-stage structure runs: deposit of 20-30% on contract signing, a mid-project milestone of 25-35% at a defined progress point such as first fix completion or equipment delivery, near-completion of 25-30% at practical completion or commissioning, and a final payment of 10-20% on handover sign-off. Percentages vary by contract size, client relationship, and the proportion of upfront materials cost in the project.

What triggers a stage invoice, and how quickly should it be sent?

A stage invoice is triggered by the specific completion event defined in the original contract - not by the calendar, the end of the month, or when it is convenient. Raise and send the invoice within one business day of the trigger event being met. Delays between milestone completion and invoicing are a direct cash flow cost, not just an administrative inefficiency.

How should variations be handled in a stage payment schedule?

Every variation should be approved in writing before the work is carried out and recorded against the job record at the time of approval. Before the final invoice is raised, review all recorded variations and include each one as a named line item. Introducing variations for the first time in the final invoice - without prior written approval - is the most reliable way to trigger a payment dispute.