Silo 1 · Global Late Payment Law

Understanding US Prompt Payment Acts
Federal & State Guide 2026

By Santanu Sarma — Mathematical Economics & Public Finance · Updated June 2026 · 12 min read

You delivered the work on time. Every deliverable. Every milestone. The government agency — or the prime contractor working for the government — signed off without a single revision request. And then the calendar pages started turning.

Day 30. Nothing. Day 60. A form email from their AP department asking for a document you already submitted. Day 90. You're on the phone with your bank discussing your line of credit, because the $47,000 you're owed is sitting in a bureaucratic queue and your rent, payroll, and software subscriptions do not care about federal payment cycles.

Here's what most contractors don't know: the government owes you more than $47,000. The moment that invoice crossed its due date, a federal statute — the Prompt Payment Act, codified at 31 U.S.C. §§ 3901–3907 — began automatically generating interest on that overdue balance. You don't need to ask for it. You don't need a contract clause. The law puts it there automatically.

This guide explains exactly how to calculate it, how state laws stack on top of the federal Act, and how to make sure you actually collect what you're owed.

What the Federal Prompt Payment Act Actually Does

Congress passed the Prompt Payment Act in 1982 after a GAO report found that roughly 30% of federal invoice payments were arriving late — not because of disputes, but because of agency-side bureaucratic delay. The Act is now implemented through FAR Subpart 32.9 and 5 CFR Part 1315.

The core mechanic is simple: if a federal agency misses its payment deadline, it automatically owes you interest from the day after the due date. No invoice amendment required. No notice to the contracting officer. No explicit request. The statute says it plainly:

the penalty shall be paid regardless of whether the business concern requested payment of such penalty

That is unusually powerful language for a federal statute. Most government contract clauses require you to ask. This one does not.

The Standard Payment Window (FAR 52.232-25)

For most federal contracts, the agency must pay the later of two dates: 30 days after the designated billing office receives a proper invoice, or 30 days after government acceptance of the delivered work.

The word "proper" is doing a lot of work in that sentence. A technically defective invoice — wrong DUNS number, missing period of performance, incorrect contract line item number — can be returned within 7 days, and your 30-day clock restarts from zero when you resubmit. This is the mechanism most agencies use to delay without technically violating the Act.

Construction Contracts Get a Faster Clock (FAR 52.232-27)

If you're on a federal construction contract, progress payment requests get a tighter 14-day window, not 30. The government knows construction subcontractor chains can cascade quickly — a delayed payment at the top of the chain creates insolvency risk three levels down within weeks.

That 14-day window starts from the agency's receipt of a proper pay application. Miss it, and interest accrues at the same Treasury-set rate as all other Prompt Payment Act claims.

How to Calculate Your Penalty: The Exact Formula

The federal Prompt Payment Act uses simple interest only — no compounding. The calculation is the same formula you'd use for any simple interest debt:

Worked Example — $47,000 Invoice, 90 Days Late, H1 2026 Rate

$477.80 is yours, by statute, without asking. On a larger contract — say, $250,000 overdue for 90 days — that becomes $2,541 in mandatory interest. For contracts that cross a rate-reset date (January 1 or July 1), you split the calculation: days under the old rate use the old rate, days under the new rate use the new rate, then add both figures.

Does the Prompt Payment Act Apply to Subcontractors?

This is the question every subcontractor and sub-tier vendor asks, and the honest answer has two parts.

The federal statute (31 U.S.C. §§ 3901–3907) directly governs only federal agency-to-prime-contractor payments. The government is the payer; the prime contractor is the payee. If you're a sub, you're one step removed from the statute.

But that's not the end of the story.

The FAR Clause That Protects Subcontractors

FAR clause 52.232-27 (Prompt Payment for Construction Contracts) requires prime contractors to pay subcontractors within 7 days of receiving payment from the government. Miss that 7-day window and the prime owes interest at the same federal rate.

This doesn't help you if the government hasn't paid the prime yet — you can't squeeze money from a prime who hasn't received it. But the moment the prime is paid, your 7-day clock starts. Document your work acceptance carefully and track the date the agency pays the prime (publicly visible in FPDS-NG for large contracts).

Your State's Subcontractor Prompt Payment Act Often Does More

Most state prompt payment statutes apply to private construction and government construction separately, and many of them give subcontractors direct statutory rights against primes — without needing to wait for a federal pay event first. California's Public Contract Code § 7107 is the most aggressive: it imposes a 2% per month penalty on retainage withheld more than 60 days after project completion, running against the owner and the prime independently.

State Prompt Payment Laws: 10-State Comparison Table

Every state has its own version of a prompt payment statute — and they vary dramatically in rate, payment window, and who is covered. The federal Act sets the floor for government contracts; state acts fill the gaps for state government and private construction work.

One important rule: these state rates and windows can change annually. Always confirm the current figure with your state controller or AG website before relying on a number in any table — including this one.

Rates and windows are subject to change. Always verify with your state controller, AG office, or a licensed attorney before relying on a specific figure for a legal claim.

Three Things That Will Kill Your Prompt Payment Act Claim

The statute is automatic, but that doesn't mean the money appears without effort. Contracting officers routinely contest penalty claims on procedural grounds, and three issues account for the vast majority of rejected or reduced claims.

1. A Defective Invoice That Restarted Your Clock

A federal billing office can return a technically deficient invoice within 7 days and restart the 30-day clock from the date you resubmit a corrected version. The 7-day return window is strict — if they fail to return it within 7 days, they lose the right to claim it was defective. But most contractors don't know this, and agencies use the 7-day return as a delay tool routinely.

Track the date of each invoice submission and each return. If an agency tries to return an invoice on day 9, that return is out of time — your original due date stands.

2. Missing or Disputed Acceptance Date

Your 30-day window starts from the later of invoice receipt or work acceptance. If there's any open question about whether the government formally accepted your deliverable, the clock may not have started at all — or the agency will argue it hasn't.

Get written acceptance confirmation for every deliverable. An email from the Contracting Officer's Representative (COR) saying "work accepted" is enough. Without it, you're arguing against a bureaucracy with no paper trail.

3. Using a Stale Interest Rate in Your Claim

The Treasury rate resets every January 1 and July 1. If you submit a penalty claim using the H2 2025 rate (which was different from the current 4.125%) for days that fell in H1 2026, the agency will reject the computation. They're not wrong — the rate matters, and getting it wrong hands them an easy procedural out.

Use the rate published at the Treasury Bureau of the Fiscal Service for the specific half-year period each day of overdue payment falls in. If your delinquency spans a reset date, split the calculation as shown earlier.

How to Actually File a Prompt Payment Act Penalty Claim

Filing a Prompt Payment Act interest claim is not the same as filing a formal contract dispute under the Contract Disputes Act (41 U.S.C. § 7101 et seq.). For most straightforward overdue invoice situations, the process is far simpler.

Step 1 — Document Everything First

Gather your invoice with submission date, the designated billing office's contact record, any deficiency notices received (and their dates), and evidence of work acceptance. If the agency uses an electronic invoicing system (IPP, MyInvoice, or similar), export the submission and receipt timestamps.

Step 2 — Calculate at the Correct Rate

Use the formula above (I = P × r × t) with the Treasury-published rate for each relevant period. Document your calculation in a simple spreadsheet. You'll need to show your work if the agency pushes back.

Step 3 — Submit a Supplemental Invoice or Written Demand

Send a written demand to the Contracting Officer — not just the billing office — citing 31 U.S.C. § 3902(a) and FAR clause 52.232-25 (or 52.232-27 for construction). Include your calculation, the applicable rate with its source citation, and the exact overdue period.

Most agencies pay within 30 days of a properly documented interest demand without further argument. The statute is unambiguous, and most contracting officers know it.

Step 4 — Escalate to the Agency Inspector General if Ignored

If the agency doesn't respond, the IG's office is your next stop. Prompt Payment Act violations are reportable, and IG offices take them seriously because they generate audit findings. A letter to the IG citing the specific overdue days and the statute usually produces payment faster than any formal legal process.

Formal escalation to the Armed Services Board of Contract Appeals or the Court of Federal Claims is reserved for large amounts or systematic non-payment — not a first response to a $477 interest claim.

The Bigger Picture: Why This Matters More Than the Dollar Amount

For a single $47,000 invoice overdue 90 days, the Prompt Payment Act generates $477 in interest. That's not life-changing. But you're not just collecting $477 — you're establishing something more important.

When you file a proper Prompt Payment Act interest demand, you signal to the contracting officer and the agency's AP department that you know the rules. Agencies — like any institution — respond to contractors who document carefully and assert their rights professionally. Agencies that know you'll enforce the Act tend to process your invoices faster the next time.

The real value of the Prompt Payment Act isn't the interest. It's the behavioral change it creates when you use it once.

And on multi-year contracts with regular progress payments — where the total value might be $2 million or more — a systematic late-payment pattern at 4.125% per annum across 20 invoices compounds into a very significant amount. Track every invoice. Claim every dollar. It's yours by law.

Frequently Asked Questions

This article is informational and reflects published federal and state statutory mechanics as of June 2026. It is not legal advice. The federal Prompt Payment Act interest rate resets semi-annually and state rates reset on varying schedules — confirm all figures with the Treasury Bureau of the Fiscal Service and your relevant state authority before relying on them for a specific claim. For disputes exceeding $25,000 or involving contested acceptance, consult a licensed government contracts attorney.