How Government Contractors Get Paid: Timelines, Invoicing, and Cash Flow

You just won your first government contract. The excitement lasts about 48 hours. Then you realize you have no idea how to actually get paid.

No one hands you a check at the contract signing. There is no Venmo for the federal government. And depending on your contract type, your first payment could be four months away.

This is the part of government contracting that nobody warns you about. Understanding how government contractors get paid is the difference between building a real business and running out of cash before your first invoice clears.

How Government Contractors Get Paid

The government pays contractors in one of four ways. The method depends on your contract type, not your preference.

Regardless of contract type, the payment lifecycle follows the same basic path:

1. You perform the work and incur costs (payroll, materials, overhead).
2. You submit an invoice through the correct electronic system.
3. The government inspects and accepts your deliverables.
4. The payment office processes your invoice against the contract.
5. Funds transfer to your bank via Electronic Funds Transfer (EFT) using the banking information in your SAM.gov registration (per FAR 52.232-33).

Here is the part that catches new contractors off guard. The payment clock does not start when you finish the work. It starts when the government receives a “proper” invoice AND accepts delivery. If your invoice has an error, the clock resets. If the government is slow to inspect your work, the clock hasn’t started.

For most new contractors, the gap between first cash outlay and first payment is roughly 120 days. You fund payroll, buy materials, and cover overhead for three to four months before the government sends a single dollar. That gap is real, and you need to plan for it.

Two of your existing articles cover the contract types that affect how you’re paid: cost-plus vs. fixed-price contracts explains the risk tradeoff, and IDIQ contracts explained covers how task order billing works.

What Makes an Invoice “Proper” Under the FAR

A single missing field on your invoice resets the payment clock to zero. The Federal Acquisition Regulation (FAR) defines exactly what a “proper invoice” must contain. Miss any one element and the government can reject your invoice, and your corrected resubmission starts a fresh waiting period.

The 10 Required Elements (FAR 32.905)

Every invoice you submit to the federal government must include these 10 items per FAR 32.905(b):

1. Contractor name and address as they appear on the contract (not your “doing business as” name, not an abbreviation)
2. Invoice date and invoice number
3. Contract number, order number, and line item number
4. Description, quantity, unit of measure, unit price, and extended price for each line item
5. Shipping information (shipment number, date, bill of lading number) if applicable
6. Name and address of the official designated to receive payment
7. Contact information (name, title, phone, address) for invoice inquiries
8. Taxpayer Identification Number (TIN)
9. Electronic funds transfer banking information (or confirmation it’s current in SAM.gov)
10. Any other information or documentation required by the contract (check Section G and Section H of your contract for agency-specific requirements)

That last element is the one that trips up new contractors. Your contract may require additional documentation beyond the standard nine. Check Section G (Contract Administration Data) and Section H (Special Contract Requirements) as soon as you receive your award.

The Rejection Clock Reset

When you submit an invoice, the government has 7 days to review it and tell you if something is wrong (3 days for meat, fish, and poultry contracts). If they find a defect, they return the invoice. Your corrected resubmission starts the payment clock over from scratch.

This means a single typo can cost you a month. Contractors report that even abbreviating “Street” to “St.” when the contract spells it out can trigger a rejection. If your company has relocated or changed its legal name since the contract was awarded, you need a contract modification before your invoices will process.

The COR Bottleneck

On Department of Defense (DoD) contracts, payment cannot process until the Contracting Officer’s Representative (COR) submits a receiving report confirming acceptance of your work. If the COR is on leave, overloaded, or unfamiliar with the invoicing system, your properly submitted invoice sits untouched. You have zero control over this step.

Experienced contractors build relationships with their COR early. They confirm the COR knows how to use the invoicing system and understands the timeline expectations.

Top DFAS Rejection Codes

The Defense Finance and Accounting Service (DFAS) uses specific rejection codes. Knowing these helps you prevent common errors:

Practitioner tip: Build a contract-specific invoice file on the day you receive your award. Include the contract number, every CLIN (Contract Line Item Number) and ACRN (Accounting Classification Reference Number), the submission system, and the payment office address. Update this file every time you receive a contract modification. This single habit prevents the majority of invoice rejections.

For more on the accounting systems that support proper invoicing, see our guide to Defense Contract Audit Agency (DCAA)-compliant accounting. And for the broader regulatory framework your invoices must follow, check our FAR compliance guide.

WAWF vs. IPP: Which System You’ll Use

The federal government uses two electronic invoicing systems. Your contract determines which one.

WAWF (Wide Area WorkFlow) is the DoD’s mandatory invoicing platform, hosted within the Procurement Integrated Enterprise Environment (PIEE) at piee.eb.mil. If you hold a DoD contract, you’ll use WAWF per Defense Federal Acquisition Regulation Supplement (DFARS) 252.232-7006. The process is a multi-step chain: you submit your invoice, the COR submits a receiving report confirming acceptance, and then DFAS processes payment. WAWF validates your submission against the contract data loaded into the system. Mismatches trigger automatic rejections.

IPP (Invoice Processing Platform) is the civilian agency system run by Treasury’s Bureau of the Fiscal Service at ipp.gov. Over 106 federal agencies and 133,000 vendors use it. IPP is simpler than WAWF with a single-reviewer approval workflow, and it’s free for both agencies and vendors. It pulls your contractor information from SAM.gov, so discrepancies between systems will cause processing failures.

Register before your first invoice is due. During your post-award kickoff meeting, ask the contracting officer which system your contract uses. Then register immediately. Many agencies publish their own invoice submission guides with requirements beyond the FAR minimum. Ask for those too.

Both systems require your SAM.gov registration to be current. If your registration lapses, payments stop across all your contracts.

Your Rights Under the Prompt Payment Act

Federal law requires the government to pay you within 30 days of receiving a proper invoice. If they don’t, they owe you interest. This isn’t a suggestion. It’s the Prompt Payment Act (31 U.S.C. 3901-3907), and it applies to every federal contract.

The Payment Timeline

Automatic Interest Penalties

When the government misses a payment deadline, interest accrues automatically per 5 CFR Part 1315. You don’t have to file a claim or send a demand letter. The payment office is required to calculate and include the interest when they process your late payment.

The current Prompt Payment interest rate is 4.125% per annum for January through June 2026, set by the Treasury Department every six months.

If the automatic interest isn’t included with your late payment, submit a written demand within 40 days of receiving the payment. This demand entitles you to the unpaid interest plus an additional penalty. It’s a right established by the Prompt Payment Act, not a favor you’re asking for.

Accelerated Payments for Small Businesses

Under Office of Management and Budget (OMB) Memorandum M-11-32, agencies have a policy goal of paying small business prime contractors within 15 days. This is a policy goal, not a legal mandate, so it doesn’t create enforceable rights beyond the Prompt Payment Act deadline. But it’s worth asking your contracting officer about during post-award kickoff.

Prime contractors who receive accelerated payments are required to pass them through to small business subcontractors per FAR 52.232-40. On construction contracts, primes must pay subcontractors within 7 days of receiving government payment per FAR 52.232-27.

What Happens During a Government Shutdown

During the Fall 2025 government shutdown (43 days), payment offices were furloughed and no invoices were processed. Consider what that means for a small IT reseller with a $2 million annual contract. Six weeks of frozen payments means covering payroll, rent, and subcontractors entirely out of pocket. Credit lines get drawn down. Prompt Payment Act interest accrues but doesn’t help you make payroll today.

Small business contractors bear the brunt of shutdowns. The U.S. Chamber of Commerce estimates that 65,500 small businesses have nearly $3 billion per week at risk when payment offices close. Unlike federal employees, contractor workers don’t receive back pay when the government reopens. For more on regulatory changes affecting contractors, see our FAR Part 19 overhaul guide.

Contract Financing: Getting Paid Before Final Delivery

You don’t always have to wait until the work is done. Three financing mechanisms built into the FAR let you receive government payments during contract performance.

Performance-based payments are the government’s preferred financing method per FAR policy. If your contract has measurable milestones, ask about performance-based payment provisions during negotiations. They give you cash earlier in the contract lifecycle.

The DoD small business progress payment rate of 95% comes from Class Deviation 2020-O0010 Revision 2, originally issued during the COVID-19 emergency and still active for small business DoD contracts as of 2026. If you’re bidding on a DoD contract, confirm this rate is included in the solicitation.

For more on how to approach your first contract bid, see how to bid on government contracts.

How to Survive the Cash Flow Gap

The 120-day gap between your first expense and your first payment is the single biggest financial risk for new government contractors. More than half of all small businesses cite paying operating expenses as a major challenge, per the Federal Reserve’s 2024 Small Business Credit Survey. A separate Bluevine survey found that 39% of small businesses have less than one month of cash on hand. Government contracting makes both problems worse because payment timelines are longer than most commercial work.

Experienced contractors don’t just cope with the cash flow gap. They plan for it before signing their first contract.

Before Your First Contract

• Build 3 to 6 months of operating reserves. Calculate your monthly burn rate (payroll, rent, insurance, overhead) and save enough to cover it for the time between your first expense and your first expected payment.
• Establish a business line of credit while your finances are healthy. Banks lend to healthy businesses. They don’t lend to desperate ones. Get the credit line before you need it.
• Research invoice factoring companies that specialize in government receivables. Know their terms, fees, and approval process so you can move fast if cash gets tight.

The 13-Week Rolling Cash Flow Forecast

This is the industry gold standard for government contractor cash management. Every week, you project your cash inflows and outflows for the next 13 weeks. The forecast answers one question: when will I run out of money if nothing changes?

Your forecast should track:

• Expected government payments (by invoice date plus 30-45 days for processing)
• Payroll obligations (your largest recurring outflow)
• Subcontractor payments (if you’re a prime)
• Rent, insurance, and fixed overhead
• Materials and project-specific costs

Update the forecast every Monday. When you spot a week where outflows exceed inflows, you have 13 weeks to solve it. That’s enough time to arrange financing, adjust vendor terms, or invoice faster on another contract.

Invoice Factoring for Government Contracts

Invoice factoring lets you sell your government receivables to a financing company for 80-90% of the invoice value within 24 to 48 hours. The factoring company collects the full amount from the government when the invoice is paid.

This works for government contracts because approval is based on the government’s creditworthiness, not yours. The federal government is the most reliable payer in the country. It just pays slowly.

The legal foundation is the Assignment of Claims Act (FAR Subpart 32.8), which allows contractors to assign their right to receive payment to a financing institution. The assignment must cover all unpaid amounts on the contract and go to only one financial institution.

Factoring is not free. Fees typically run 1-5% of the invoice value. Weigh that cost against the alternative: missing payroll or defaulting on a subcontractor payment.

SBA Financing Options

The Small Business Administration (SBA) offers two financing products designed for government contractors:

• Contract CAPLines: Working capital lines of credit up to $5 million, secured by the contract receivables. Funds can only be used for direct labor and material costs on the specific contract. Terms up to 10 years.
• 7(a) Loans: General-purpose business loans for longer-term capital needs. The SBA approves tens of thousands of 7(a) loans each year, totaling tens of billions of dollars. Check SBA.gov for the latest annual lending data.

Start the SBA loan process early. Approval takes weeks to months, not days.

Align Your Payables to Your Receivables

If the government pays you in 30-45 days, negotiate Net 45 or Net 60 terms with your own vendors and subcontractors. This is standard practice in government contracting. Most vendors who work with GovCon primes understand the payment cycle and will agree to extended terms if you communicate openly.

For more on managing the financial side of government contracting, see our guides to indirect cost rates and how to start government contracting.

Frequently Asked Questions

How long does it take to get paid on a government contract?

The Prompt Payment Act gives agencies a deadline tied to invoice receipt and acceptance of work. In practice, your first payment often arrives 60 to 120 days after your first expense because you must perform the work, prepare documentation, submit through the correct system, and wait for the COR to confirm acceptance before the clock starts.

What happens if the government pays my invoice late?

Interest accrues automatically under the Prompt Payment Act. You don’t need to file a claim or send a demand letter. If the interest isn’t included with your late payment, submit a written demand to the payment office within 40 days. Track every late payment because the interest adds up across multiple invoices.

What is a “proper invoice” under the FAR?

FAR 32.905 defines 10 required elements that make an invoice proper. The most common rejection triggers are mismatched contractor names, incorrect CLIN or ACRN references, and expired SAM.gov registrations. Build a contract-specific invoice template on award day so you’re not guessing when your first invoice is due.

What is WAWF and do I have to use it?

Wide Area WorkFlow (WAWF) is the DoD’s electronic invoicing system accessed through piee.eb.mil. If you hold a DoD contract, WAWF is mandatory per DFARS 252.232-7006. Civilian agency contracts use the Invoice Processing Platform (IPP) at ipp.gov. Register in your required system before your first invoice is due.

Can I use invoice factoring on government contracts?

Yes, the Assignment of Claims Act makes government receivables assignable to a financing institution. Factoring works best when you have a cash gap between payroll obligations and expected payment. Compare factoring fees (typically 1-5% of invoice value) against the cost of missing payroll. Some factoring companies specialize in government contracts.

What happens to contractor payments during a government shutdown?

Payment offices close during a shutdown, so no invoices are processed until the government reopens. Contractor employees don’t receive back pay, unlike federal employees. The Prompt Payment Act still applies after the shutdown ends, so agencies must pay interest on delayed invoices once they resume operations.

Does my prime contractor have to pay me on time as a subcontractor?

On construction contracts, FAR 52.232-27 requires primes to pay subs promptly after receiving government payment. FAR 52.232-40 requires primes who receive accelerated payments to pass them through to small business subcontractors. For non-construction contracts, subcontractor payment terms are governed by your subcontract agreement, so negotiate those terms before signing.

Next Steps

1. Check your SAM.gov registration. Go to sam.gov and confirm your banking information is current and your registration won’t expire before your first invoice is due.
2. Identify your invoicing system. Ask your contracting officer whether you’ll use WAWF (piee.eb.mil) or IPP (ipp.gov) and register before your first invoice.
3. Build your contract invoice file. Pull the contract number, CLIN structure, ACRN codes, and payment office address from your awarded contract. Store them in one document you can reference for every invoice.
4. Create a 13-week cash flow forecast. Map your expected expenses against your projected invoice dates. Identify any week where outflows exceed inflows and plan your bridge now.
5. Talk to your bank. Ask about government contract lines of credit or SBA CAPLines before you need them.