Tool 2 of 3 · Paying the builder
Stage payment and retention calculator
Enter the contract sum and how you plan to pay. The worksheet builds a dated schedule showing what is held back at each stage, what you pay, and when the retention comes back to the builder.
How this is calculated
- Deposit = contract sum × deposit %, paid on the start date.
- Each stage is valued at contract sum × that stage's share (equal shares unless you set your own).
- Retention held at each stage = stage value × retention %. Total held = contract sum × retention %.
- Deposit credit: the deposit is deducted from the stages in the same proportions, so you never pay it twice.
- You pay at each stage = stage value − retention − deposit credit.
- Half the retention is paid at practical completion (start date + build length). The rest is paid after the rectification period, once defects are made good.
Pennies are rounded so the last stage absorbs any rounding and the total always equals the contract sum. Dates are estimates spaced evenly across the build; real stages depend on progress. This is a planning aid, not a payment certificate. Under JCT Minor Works the contract administrator values work at each interim payment; under milestone plans each stage is paid when its definition is met. See retention and stage payments and the JCT payment clauses.