Progress Payment Calculator
Advance recovery, retention and the amount due this period.
Inputs
Result
Formula
| Advance | contract × advance % |
| Threshold | contract × recovery start % |
| Recoverable | (cumulative − threshold) × advance % |
| This period | recoverable now − recoverable before |
| Retention | period value × retention % |
| Amount due | period value − recovery − retention |
A 1 million contract with 200,000 this period and 400,000 before, 20% advance, 30% threshold and 3% retention: 200,000 advance, 300,000 threshold, 40,000 recovered, 6,000 retention — 154,000 due.
FAQ
Why set the recovery threshold at 30%?
Because the advance exists to mobilise: buying materials and bringing in plant. By the time 30% of value is certified, materials have turned into work and progress payments sustain the site, so recovery no longer starves it. A lower threshold squeezes the contractor sooner; too high and the client carries more risk of misuse.
Can retention be replaced by a bond?
Yes, and more projects do. Rules on clearing construction deposits state that a bank guarantee or insurance policy may replace cash retention and the client must not refuse. A bond frees 3% of cash flow for a fee of roughly 1-2% a year, and it is worth writing into the contract.
What if the client delays payment?
Check the contractual payment period, typically 28-56 days; late payment carries interest at the market loan rate. Construction price priority rights protect the contractor, but the window is 18 months from completion and lapses after that. In practice the decisive thing is complete measurement and sign-off records — without them, a good case goes nowhere.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.