Progress billing is a method of invoicing a customer for work completed to date on a long-duration project, rather than waiting until the entire project is finished to bill the full amount. It allows a contractor to receive cash throughout a project that might otherwise take months, matching payment to work actually performed along the way.
A contract's total value is billed incrementally, tied to either a percentage of completion, specific milestones, or a defined billing schedule, rather than as one lump sum at project completion. Each progress invoice reflects the value of work done since the last billing, not the entire remaining contract.
EXAMPLE
A $500,000 contract, 30% complete this period, was previously billed to 20% complete.
Cumulative billing to date = $500,000 × 0.30 = $150,000.
This period's invoice = $150,000 − $100,000 (previously billed) = $50,000.
The right method depends on how measurable the work is. Percentage of completion works well for work that progresses fairly continuously; milestone billing works better when a project has clear, discrete phases; unit-price billing works best when work output can be precisely counted.
Progress billing is the general concept: invoicing incrementally as work is completed. AIA billing is one specific, standardized implementation of progress billing, using the G702 and G703 forms and typically following the percentage-of-completion method. A contractor can do progress billing without using the AIA format at all, particularly on smaller or private projects where the formal AIA process is not contractually required.
For accounting purposes, progress billing is closely related to the percentage-of-completion method of revenue recognition, where a contractor recognizes revenue as work is performed rather than only when the project is finished or when cash is collected. The amount billed and the amount of revenue recognized are related but not always identical figures, since billing terms and recognized revenue can diverge based on contract specifics.
This creates two balance sheet items worth understanding: billings in excess of costs, when a contractor has billed more than the revenue recognized to date, and costs in excess of billings, the reverse situation, when work performed and costs incurred exceed what has been billed so far.
An inflated percentage-complete claim overstates both revenue and cash collected relative to actual project status, which can mask a project that is falling behind or running over budget until the gap becomes too large to hide. An understated claim, less common but still problematic, leaves cash on the table that the contractor has legitimately earned.
Validating each progress invoice against prior billing history and, where available, independent progress verification is what keeps the billing an accurate reflection of actual project status rather than a number that has drifted from reality over the course of a long project.
