Federal government purchase orders are a simplified contracting tool agencies use for buys up to $350,000, and they become binding contracts the moment a vendor accepts them, either in writing or by starting performance. The rules live mainly in Part 13 of the Federal Acquisition Regulation, and the payment side carries real teeth: once the government accepts what you delivered, it has 30 days to pay a proper invoice, with automatic interest running against it if it doesn’t.
When a Purchase Order Is the Right Instrument
Two dollar figures set the boundaries. As of October 1, 2025, the micro-purchase threshold is $15,000 and the simplified acquisition threshold is $350,000.1Acquisition.GOV. Threshold Changes – October 1st, 2025 Below $15,000, agencies typically use a government purchase card with minimal competition requirements. Between $15,000 and $350,000, the purchase order is the standard tool: the agency must seek reasonable competition but doesn’t need sealed bids or negotiated proposals.2eCFR. 48 CFR Part 13 – Simplified Acquisition Procedures
Those ceilings rise during declared emergencies, major disasters, and military contingency operations. Inside the United States, the micro-purchase threshold rises to $25,000 and the simplified acquisition threshold to $1 million. For operations outside the country, the figures climb to $40,000 and $2 million.3Federal Register. Federal Acquisition Regulation: Inflation Adjustment of Acquisition-Related Thresholds
How Acceptance Creates the Contract
A purchase order starts life as a one-sided offer from the government: buy these items, at this price, by this date. No contract exists yet. It becomes binding when the vendor accepts, either by written acknowledgment or by starting work.2eCFR. 48 CFR Part 13 – Simplified Acquisition Procedures The second path matters. If you ship the goods without signing anything, shipping itself is acceptance, and you are on the hook for performance.
Before acceptance, you can review the terms and walk away. After performance begins, both sides are locked in: the government must pay for conforming goods, and you must deliver what the order specifies.
What Belongs on the Order
The main form for commercial buys is Standard Form 1449, “Solicitation/Contract/Order for Commercial Products and Commercial Services.”4Acquisition.GOV. Federal Acquisition Regulation Part 53 – Forms Whatever form the agency uses, every order must include the quantity of supplies or scope of services, a delivery deadline, inspection and acceptance terms, and the shipping arrangement.5eCFR. 48 CFR 13.302-1 – General Unit price and extended price complete the picture.
Shipping Terms
Most domestic orders specify FOB Destination. You bear all shipping costs and remain responsible for the goods until they arrive at the government facility, including any loss or damage in transit.6Acquisition.GOV. 52.247-34 F.o.b. Destination FOB Origin is less common and shifts risk to the government once the goods leave your dock. Read the term carefully; a vendor who assumes the wrong one may end up paying for a damaged shipment.
Clauses Incorporated by Reference
Rather than reprinting pages of regulatory text, purchase orders incorporate FAR clauses by reference. Those clauses apply with the same force as if they were printed in full.7Acquisition.gov. 48 CFR 52.252-2 – Clauses Incorporated by Reference They cover inspection rights, termination, labor standards, and other obligations. Request the full text of any unfamiliar clause before accepting; the contracting officer must provide it.
Registering to Receive an Order
Before receiving any federal purchase order, a business must register in the System for Award Management at SAM.gov. Registration is free, and the system assigns a Unique Entity ID used across federal transactions.8SAM.gov. Entity Registration During registration you enter banking information for electronic funds transfers, classify the business under NAICS codes, and make representations about ownership and size status.
Registration must be renewed annually. If it lapses, you cannot receive new awards, and in some cases you cannot receive payment on existing ones. Start renewal at least 60 days before expiration.9SAM.gov. Entity Registration The Federal Service Desk is the only authorized help channel, available weekdays from 8 a.m. to 8 p.m. Eastern. Third parties frequently offer to handle SAM registration for a fee. Since the process is free and official support costs nothing, paying an intermediary is unnecessary.
Small Business Set-Asides in This Range
Every purchase order between $15,000 and $350,000 is automatically set aside for small businesses unless the contracting officer determines that fewer than two small firms can offer competitive prices at fair market value.10eCFR. 48 CFR 19.502-2 – Total Small Business Set-Asides This is a mandatory presumption. Even if only one acceptable small business bids, the contracting officer should award to that firm. Only if no acceptable small business offers come in does the requirement drop and the agency resolicit without restriction.
Within that pool, firms certified under the SBA’s 8(a) program, service-disabled veteran-owned small businesses, women-owned small businesses, and HUBZone companies can receive sole-source or restricted-competition awards, depending on the dollar value and the agency’s socioeconomic goals.
Getting Paid: The Proper Invoice
After the government inspects and accepts what you delivered,11eCFR. 48 CFR Subpart 46.4 – Government Contract Quality Assurance you submit an invoice. Getting it right the first time matters, because a defective invoice restarts the payment clock. The agency’s billing office must return a non-compliant invoice within seven days, and the 30-day payment window doesn’t begin until the corrected version arrives.12eCFR. 48 CFR 32.905 – Payment Documentation and Process
A proper invoice includes:
- Contractor name, address, and the name of the official designated to receive payment
- Invoice date, invoice number, and the contract or order number, with line item numbers
- Description, quantity, unit of measure, unit price, and extended price for each item or service
- Shipment number, shipment date, and applicable discount terms
- Taxpayer identification number and EFT banking information, if the contract requires them
- Name, title, phone number, and address of a point of contact for invoice problems
Most agencies require electronic submission through the Invoice Processing Platform or a similar portal. Paper invoices slow everything down.
Payment Deadlines and Late-Payment Interest
The Prompt Payment Act sets the clock. For most goods and services, payment is due 30 days after the agency receives a proper invoice, or 30 days after acceptance of the delivery, whichever comes later.13Acquisition.GOV. Subpart 32.9 – Prompt Payment Construction progress payments run on a 14-day clock. Meat and fresh fish must be paid within 7 days of delivery; perishable agricultural commodities within 10 days.
When the government misses a deadline, interest runs automatically from the day after the due date, whether or not the vendor asks for it.14Office of the Law Revision Counsel. 31 USC 3902 – Interest Penalties The rate is tied to the 91-day Treasury bill rate published by the Secretary of the Treasury. For the first half of 2026, that rate is 4.125%.15Bureau of the Fiscal Service. Prompt Payment
Interest that remains unpaid after 30 days is added to the principal, and interest then accrues on the combined amount.14Office of the Law Revision Counsel. 31 USC 3902 – Interest Penalties A lack of available funds does not excuse late payment; the interest is still owed. If you receive a late payment without the accompanying interest, submit a written demand within 40 days to trigger eligibility for an additional penalty on top of the interest already owed.
Modifications After Issuance
The government can modify a purchase order after issuance. Each modification identifies the original order and carries its own sequential modification number.16Acquisition.GOV. 13.302-3 Obtaining Contractor Acceptance and Modifying Purchase Orders The contracting officer may require your written acceptance when necessary to ensure compliance or when agency rules demand it. Typical modifications adjust quantities, extend delivery dates, or change the delivery location. Modifications that change price or scope without vendor agreement are where disputes usually begin.
Termination for Convenience and for Default
The government can cancel a purchase order at any time for its own convenience, even when the vendor has done nothing wrong. Under a convenience termination, you stop work immediately and are paid a percentage of the contract price reflecting the percentage of work completed, plus reasonable costs caused by the termination itself.17eCFR. 48 CFR 52.213-4 – Simplified Acquisitions (Other Than Commercial Products and Commercial Services) You cannot recover anticipated profits on unperformed work.
A termination for default is different. If you fail to deliver, violate the contract terms, or cannot give adequate assurance of future performance, the government can terminate for cause. You receive nothing for unaccepted goods or services, and you become liable for the cost the government incurs buying the items elsewhere. Those reprocurement costs can include the higher price paid to a replacement vendor plus internal administrative expenses tied to the default, such as staff time, printing, and travel.
One safeguard: if a reviewing authority later determines the default termination was improper, it converts automatically into a termination for convenience.17eCFR. 48 CFR 52.213-4 – Simplified Acquisitions (Other Than Commercial Products and Commercial Services) You then receive what a convenience termination would have paid, which limits the damage from an agency’s bad call.
Disputing a Payment or Termination Decision
If you disagree with a contracting officer’s decision on a payment, a claim, or a termination, start with a written claim to that same contracting officer. Claims must be filed within six years of when the dispute arose.18Acquisition.GOV. Part 33 Protests, Disputes, and Appeals
The contracting officer has 60 days to decide claims of $100,000 or less. For larger claims, the officer must either decide within 60 days or tell you when a decision will come. If the officer misses the required timeframe, the claim is treated as denied and you can appeal immediately.
Two appeal routes exist after denial:
- Agency Board of Contract Appeals: file written notice within 90 days of receiving the contracting officer’s decision.
- U.S. Court of Federal Claims: file a direct lawsuit within 12 months of the decision date.
These deadlines are firm. Miss the 90-day board window and that route closes, though the 12-month court option remains if it hasn’t also expired. If you anticipate a dispute, document everything from the moment something goes wrong. The paper trail often decides the outcome.