RenovationRouteFree tool · Federal construction
Prompt Payment Act interest calculator
The government paid late. Figure out when the payment was due, how many days late it was, and the interest the agency owes you, using the Treasury rate that applies.
Current rate 4.75% Jul 1, 2026 to Dec 31, 2026
General information, not legal advice. The payment clauses in your contract control. Rates verified against the Bureau of the Fiscal Service on Sep 29, 2026.
When the payment is due
Due dates on federal construction contracts
14 days
Progress payments, after the billing office receives a proper payment request. The contract can set a longer period.
30 days
Final payment, counted from the later of invoice receipt or acceptance. Acceptance is deemed 7 days after you finish the work.
30 days
Released retainage, after the contracting officer approves the release, unless the contract sets a date.
These come from FAR 52.232-27, Prompt Payment for Construction Contracts, which reads the same in the RFO deviation text. One wrinkle: 5 CFR 1315.14 says unpaid released retainage starts earning interest after a date in the contract or, if none, 30 days after final acceptance, while the FAR clause says 30 days after the contracting officer approves the release. This calculator follows the FAR clause, since that is what is in your contract.
The rules
How Prompt Payment interest is calculated
- Interest runs from the day after the due date through the day you are paid.
- One rate applies to the whole late period: the rate in effect on the day after the due date. A rate change partway through does not split the calculation.
- Interest compounds every 30 days, for up to one year, on a 360-day year.
- Interest stops accruing after one year, or once you file a Contract Disputes Act claim for it. This calculator stops counting at 365 days.
- If the due date falls on a Saturday, Sunday, or federal holiday, the agency can pay on the next working day with no interest.
- No interest is owed on amounts held back under the contract, on payments delayed by a dispute over amount or compliance, or when the total is under $1.
- The agency is supposed to pay interest automatically, without a request. If it pays the invoice but not the interest within 10 days, you can demand an additional penalty in writing within 40 days of the payment.
The math is the same one Treasury's own calculator uses: amount × (1 + rate/12)n × (1 + rate/360 × d) minus the amount, where n is the number of full 30-day periods and d is the leftover days.
Treasury rates
Prompt Payment interest rates since 2020
Set every six months by the Treasury. Verified Sep 29, 2026.
| Period | Rate |
|---|---|
| Jul 1, 2026 to Dec 31, 2026 | 4.75% |
| Jan 1, 2026 to Jun 30, 2026 | 4.125% |
| Jul 1, 2025 to Dec 31, 2025 | 4.625% |
| Jan 1, 2025 to Jun 30, 2025 | 4.625% |
| Jul 1, 2024 to Dec 31, 2024 | 4.875% |
| Jan 1, 2024 to Jun 30, 2024 | 4.875% |
| Jul 1, 2023 to Dec 31, 2023 | 4.875% |
| Jan 1, 2023 to Jun 30, 2023 | 4.625% |
| Jul 1, 2022 to Dec 31, 2022 | 4% |
| Jan 1, 2022 to Jun 30, 2022 | 1.625% |
| Jul 1, 2021 to Dec 31, 2021 | 1.125% |
| Jan 1, 2021 to Jun 30, 2021 | 0.875% |
| Jul 1, 2020 to Dec 31, 2020 | 1.125% |
| Jan 1, 2020 to Jun 30, 2020 | 2.125% |
Retainage
How much retainage is being held
Under FAR 32.103, a contracting officer may hold back part of a progress payment only when you have not made satisfactory progress, decides the amount case by case, and may not withhold more than 10 percent of the approved estimated amount. Retained amounts are paid promptly once all contract requirements are done. The RFO text of Part 32 says the same.
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