Payment Certificate Calculator
Work out the net amount due on an interim payment certificate after retention, advance payment recovery and VAT — the way a Saudi IPC is actually built up.
Calculator
How the calculation works
Work executed this period = cumulative value to date minus the cumulative total of the previous certificates. Retention and the advance-payment recovery percentage are deducted from that period value, VAT is calculated on the period value, and what remains is the net payable.
Frequently asked questions
Why is a payment certificate calculated cumulatively?
Because quantities are measured cumulatively from the start of the project and everything previously certified is then deducted. An error in an earlier certificate self-corrects in the next.
When is retention released?
Commonly half at preliminary handover and the balance at final acceptance once the defects liability period ends. The contract wording governs, so read the clause before you assume.
How is the advance payment recovered?
Usually as a fixed percentage of each certificate until the advance is fully repaid, sometimes starting only once progress passes an agreed threshold. That rate is the input here.
Is VAT charged on the amount after retention?
No. VAT is due on the value of work executed in the period; retention is a deduction from the payment, not from the taxable value of the work.
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This calculator is also available in Arabic: حاسبة المستخلص.