Winning the contract is only half the job; getting paid on time is the other half. Federal invoicing is electronic, rule-bound and unforgiving of small errors. Most payment delays come from invoices that are not "proper" or are sent to the wrong system. This guide covers the basics.
Before your first invoice
- Check your SAM.gov registration. Your banking information for electronic funds transfer comes from your SAM.gov registration, and your electronic business point of contact there matters for system access. Keep it active and accurate.
- Read the invoicing instructions in your contract. Section G (contract administration data) or the contract's payment clauses tell you which system to use, which office to bill, what documents to attach and how often you can bill.
- Know who accepts your work. Payment generally depends on government acceptance of the supplies or services, often by a contracting officer's representative.
What makes an invoice "proper"
Under FAR 32.905, payment is based on receipt of a proper invoice and satisfactory performance. A proper invoice includes, among other things:
- Your name and address
- Invoice date and invoice number
- The contract number or other authorization, including order number and line item number
- Description, quantity, unit of measure, unit price and extended price of what you delivered
- Shipping and payment terms, where applicable
- The name and address of the official to whom payment is sent (matching the contract)
- A contact to notify if the invoice is defective
- Your TIN, if required by agency procedures, and EFT banking information as required
Read the full list in FAR 32.905 and any extra requirements in your contract. An invoice missing required items can be returned as defective, which restarts the clock.
Invoice Processing Platform (IPP)
The Invoice Processing Platform is a Treasury-run service used by many civilian agencies that manages government invoicing from purchase order to payment notification, at no charge to vendors or agencies. If your contract says to invoice through IPP, you will enroll as a vendor, receive your orders in the system, submit invoices against them, and track their status and payment notifications.
Wide Area WorkFlow (WAWF) for DoD
Defense contracts typically require electronic submission of payment requests and receiving reports through Wide Area WorkFlow, under DFARS 252.232-7003 and 252.232-7006. WAWF is accessed through DoD's Procurement Integrated Enterprise Environment (PIEE). The clause requires you to have a designated electronic business point of contact in SAM.gov and to register for access. Your contract's WAWF clause tells you which document type to use — for example, a cost voucher for time-and-materials or labor-hour line items, or a specified invoice and receiving report combination for fixed-price line items — plus the routing codes for the offices involved. Use the system's training materials before your first submission.
Other systems
Some agencies use their own payment systems or portals. Always follow the instructions in your contract or order rather than assuming.
When you should be paid
Under FAR 32.904, the due date for an invoice payment is generally the later of the 30th day after the designated billing office receives a proper invoice or the 30th day after government acceptance, with special rules for some contract types and situations. If the government pays late on a proper invoice, the payment office pays an interest penalty automatically, without a request, when the conditions in FAR 32.907 are met.
For small businesses there is also a goal of faster payment: under FAR 32.009-1, agencies are to provide accelerated payments to small business contractors to the fullest extent permitted by law, with a goal of 15 days after receipt of a proper invoice and all other required documentation, if a specific payment date is not established by contract.
Tips to avoid delays
- Invoice exactly per the contract's line items and billing frequency.
- Reference the correct contract and order numbers every time.
- Attach required supporting documents, such as timesheets for labor-hour work.
- Keep a log of submissions, rejections and payment dates.
- If an invoice is rejected, read the reason, fix it and resubmit promptly.
- Plan cash flow for the time between performing work and receiving payment, especially at the start of a contract.
Set up your back office early
Before the first invoice is due, decide who in your company submits invoices, who tracks acceptance, and who reconciles payments to your books. Create a template that already contains your contract number, line items and remit-to details, so each billing cycle is a matter of filling in quantities. A little setup prevents the most common rejections and keeps cash flowing.
If payment is late
First, confirm the invoice was accepted as proper and that the government recorded acceptance of the work. Then contact the payment office or the contact listed in your contract with the invoice number and submission date. Most delays are resolved by fixing a missing document or routing code.
Frequently asked questions
How long does the government take to pay?
Under FAR 32.904, the general due date is 30 days after receipt of a proper invoice or government acceptance, whichever is later, with exceptions. Agencies also have a goal of paying small businesses within 15 days where possible (FAR 32.009-1).
Is IPP free for vendors?
Yes. IPP describes itself as available at no charge to federal agencies and vendors.
What is WAWF?
Wide Area WorkFlow, DoD's system for electronic payment requests and receiving reports, accessed through the PIEE portal.
Do I get interest if the government pays late?
When the FAR 32.907 conditions are met — including a proper invoice and no dispute over performance — the payment office pays an interest penalty automatically.
This guide is general information, not legal advice. Rules change — always check the solicitation and the official sources linked here.