Accounts Payable Process Flow with Real Examples
From Purchase Requisition to final payment — understand every step of the AP cycle with real companies, stories, and diagrams.
What is Accounts Payable — and Why Does It Matter?
Every business buys things — raw materials, software subscriptions, office supplies, professional services. But buying something and paying for it are two very different events in accounting. The gap between those two events is managed by a system called Accounts Payable (AP).
Accounts Payable is the lifeblood of a company's financial operations. It is the process by which a company manages, tracks, and settles its short-term obligations to suppliers and vendors. Done well, AP keeps suppliers happy, prevents fraud, maintains cash flow, and gives leadership accurate visibility into what the company owes at any moment.
Done poorly, AP leads to duplicate payments, missed early-payment discounts, strained vendor relationships, regulatory penalties, and — in extreme cases — massive fraud losses. (We'll share a real story about each of these later in this guide.)
The big picture: In 2024, the global AP automation market was valued at over $3.1 billion USD. Companies that automate AP report an average cost per invoice of $2.36 — versus $15.97 for fully manual processes. That's an 85% cost reduction just by systematising the process you're about to learn.
In this guide, we walk through the complete AP cycle — all five core stages: Purchase Requisition (PR), Purchase Order (PO), Goods Receipt Note (GRN), Invoice Processing, and Payment — with definitions, real-world examples, a flow diagram, real company stories, a 10-question quiz, and a comprehensive FAQ.
Whether you are a finance student, a business owner, an operations manager, or simply someone curious about how large companies manage money, this guide covers everything you need.
Key Terms You Need to Know
Before diving into the process, let's ground ourselves in precise definitions. These terms are used universally across finance teams, ERP systems, and auditors.
Accounts Payable (AP) — A balance sheet liability account representing money a company owes to its creditors (vendors/suppliers) for goods or services already received but not yet paid for. It is classified as a current liability because it is typically due within 30–90 days.
Purchase Requisition (PR) — An internal document raised by an employee or department requesting that the purchasing team procure specific goods or services. It is the first step in the procurement process and requires approval before a purchase order can be generated.
Purchase Order (PO) — A formal, legally binding commercial document issued by the buyer to the seller, committing to purchase specific goods or services at an agreed price and quantity. A PO number is the key reference that links every subsequent document in the AP cycle.
Goods Receipt Note (GRN) — An internal document (also called a receiving report) that confirms the physical receipt of goods or completion of services as ordered. It matches the actual delivery against the PO and is essential for the three-way match process.
Invoice — A commercial document issued by the vendor to the buyer requesting payment for goods or services delivered. It includes invoice number, date, line items, total amount, payment terms (e.g. Net 30), and bank details.
Three-Way Match — The validation process of comparing three documents — PO, GRN, and Invoice — to ensure they all agree on quantity, price, and description before payment is authorised. This is the single most important fraud-prevention control in AP.
AP Aging Report — A summary of outstanding invoices categorised by how long they have been unpaid (0–30 days, 31–60 days, 61–90 days, 90+ days). Used to manage cash flow, prioritise payments, and flag overdue obligations.
Payment Terms — The agreed conditions under which a buyer will pay the seller. Common examples: Net 30 (full payment within 30 days), 2/10 Net 30 (2% discount if paid within 10 days, otherwise full payment within 30), Net 60, or COD (Cash on Delivery).
Key Roles in the AP Process
| Role | Department | Responsibility |
|---|---|---|
| Requester | Any department | Initiates PR; identifies the need for goods/services |
| Budget Owner | Finance / Department Head | Approves PR against budget availability |
| Procurement Officer | Procurement | Selects vendor, negotiates terms, issues PO |
| Receiving Team | Warehouse / Operations | Physically inspects and documents goods receipt (GRN) |
| AP Clerk | Finance | Receives invoice, performs three-way match, books liability |
| AP Manager | Finance | Reviews exceptions, approves payments above threshold |
| CFO / Treasury | Finance | Approves large payments, manages cash flow strategy |
The Complete AP Cycle: PR → PO → GRN → Invoice → Payment
The accounts payable process follows a predictable, logical sequence. Each stage has a clear input, output, and purpose. Here is the high-level overview before we dive deep into each step.
Requisition
Order
Note
Processing
Execution
Each Stage Explained in Detail
Purchase Requisition (PR)
The AP process begins long before any vendor receives a call. It starts internally, with someone inside the company identifying a need. This person — called the requester — fills out a Purchase Requisition form (physical or digital) specifying exactly what they need, why they need it, how much they expect it to cost, and when they need it.
What a PR contains:
- Description of goods or services required
- Estimated quantity and unit cost
- Suggested vendor (if known)
- Required delivery date
- Cost centre / budget code to be charged
- Business justification
Once submitted, the PR enters an approval workflow. A department head or budget owner reviews the request and checks whether funds are available in the relevant budget line. In modern ERP systems like SAP, Oracle, or Tally, this approval is automated — the system checks the budget in real time and routes the PR to the correct approver based on rules.
Real Example: An IT manager at a hospital needs 20 new laptops for nurses. She fills out a PR on the company's SAP portal specifying "20× Dell Latitude 5540, ₹65,000 each, total ₹13,00,000, required by March 15." The PR routes to the CFO for approval since it exceeds ₹10 lakh. Only after approval does the procurement team begin sourcing.
Purchase Order (PO)
Once a PR is approved, the procurement team creates a Purchase Order. Unlike a PR (which is internal), a PO is an external document — it is sent to the vendor and constitutes a legal offer to buy. When the vendor accepts it (by sending an acknowledgment or simply fulfilling the order), a legally binding contract is formed.
What a PO contains:
- PO Number — unique reference number (this is the spine of the entire AP cycle)
- Vendor name, address, and bank details
- Line items: description, quantity, unit price, total
- Delivery address and expected delivery date
- Payment terms (e.g. Net 30)
- Applicable taxes (GST, VAT, etc.)
- Authorised signatory
The PO number is critical: every subsequent document — the GRN, the invoice, and the payment — should reference the same PO number. This creates an audit trail and makes reconciliation straightforward.
PO Types:
| PO Type | When Used | Example |
|---|---|---|
| Standard PO | One-time, known quantity | Buy 500 kg of wheat |
| Blanket PO | Recurring purchases over a period | Monthly cleaning supplies for 12 months |
| Contract PO | Long-term service agreement | Annual IT maintenance contract |
| Planned PO | Scheduled future purchase | Raw material for Q3 production |
Real Example: After the hospital's PR is approved, the procurement officer issues PO #2024-IT-0312 to Dell India for "20× Latitude 5540 laptops at ₹62,000 each (negotiated), Net 30 payment terms, delivery by March 12." Dell receives the PO, acknowledges it, and schedules the shipment.
Goods Receipt Note (GRN)
When the vendor delivers the goods (or completes the service), the receiving team at the buyer's end must physically verify what was delivered against what was ordered. This verification is documented in the Goods Receipt Note.
The GRN is arguably the most underappreciated document in the AP cycle. Without a proper GRN, the company cannot prove it received what it paid for — opening the door to fraud (paying for goods never received) or disputes (vendor claims full delivery, company claims partial delivery).
What the GRN records:
- GRN number (unique)
- Reference PO number
- Date of receipt
- Vendor name
- Items received: description, quantity ordered vs. quantity received
- Condition of goods (acceptable / damaged / returned)
- Signature of receiving officer
For services (consulting, maintenance, cleaning), the GRN equivalent is often a Service Acceptance Certificate (SAC) or a sign-off by the department head confirming the service was completed satisfactorily.
Common issue — partial delivery: If 18 of the 20 laptops arrive, the GRN records "18 received, 2 pending." The AP team may only process payment for 18 units, or hold payment pending completion, depending on policy. This is a frequent source of disputes.
Real Example: On March 11, Dell's delivery arrives at the hospital. The IT technician and stores officer count and inspect all 20 laptops, confirming no damage. GRN #GRN-2024-0876 is raised on SAP referencing PO #2024-IT-0312. The GRN is digitally signed and filed, triggering the AP team to expect an invoice.
Invoice Processing & Three-Way Match
After delivery, the vendor issues an invoice requesting payment. This invoice is received by the AP team — either by email, portal upload, or physical mail. The AP clerk then performs the most critical validation in the entire AP process: the three-way match.
The Three-Way Match — How It Works:
The AP clerk places the PO, GRN, and Invoice side by side (or the ERP system does it automatically) and checks:
- Quantity match: Vendor billed for 20 laptops? GRN confirms 20 received? PO authorised 20? ✓
- Price match: Invoice price ₹62,000 per unit matches PO price? ✓
- Item match: Invoice describes "Dell Latitude 5540" matching PO description? ✓
- Vendor match: Invoice issued by Dell India (same entity as PO)? ✓
- Tax match: GST rate and amount on invoice match PO terms? ✓
If all three documents agree — the invoice is approved and posted to the General Ledger (GL) as a liability. If there is a discrepancy — say the invoice shows ₹65,000 per unit but the PO says ₹62,000 — the invoice is placed on hold and a dispute is raised with the vendor.
Invoice Exception Types:
| Exception Type | Cause | Resolution |
|---|---|---|
| Price variance | Invoice price differs from PO | Query vendor; update PO or reject |
| Quantity variance | Invoice qty exceeds GRN qty | Partial payment; raise debit note |
| Duplicate invoice | Same invoice submitted twice | Reject second copy; flag vendor |
| Missing PO reference | Vendor forgot to quote PO# | Match manually; request resubmission |
| Tax error | Wrong GST rate applied | Request credit note + corrected invoice |
Stat: According to Institute of Finance & Management (IOFM), the average AP team spends 22% of its time resolving invoice exceptions. Automation can reduce exception rates from 20–30% to under 5%.
Payment Execution
The final stage is payment — the actual transfer of funds to the vendor. By this point, three things are confirmed: the company agreed to buy it (PO), they received it (GRN), and the invoice is accurate (three-way match). Now it is time to pay.
Payment Run Process:
- Due Date Calculation: The AP system calculates the payment due date based on the invoice date and payment terms (e.g. Net 30 from invoice date March 11 = due April 10).
- Early Payment Discount Check: Does the vendor offer 2/10 Net 30? If yes, paying within 10 days saves 2%. The AP manager decides based on cash flow availability.
- Payment Proposal: AP system generates a payment proposal listing all invoices due within the payment run window.
- Authorisation: The AP Manager (and CFO for large amounts) reviews and approves the payment proposal.
- Payment Execution: Bank transfer (NEFT, RTGS, SWIFT), cheque, or virtual card payment is initiated.
- Remittance Advice: A document is sent to the vendor listing which invoices are being paid.
- GL Clearing: The AP liability account is debited (cleared), and the bank account is credited. The transaction is closed.
Payment Methods Comparison:
| Method | Speed | Best For | Risk |
|---|---|---|---|
| NEFT/RTGS (India) | Same day | Domestic vendors | Low |
| SWIFT Wire | 1–3 days | International vendors | Medium (FX risk) |
| Cheque | 3–5 days | Small vendors / one-time | Medium (lost/forged) |
| Virtual Card (P-card) | Instant | Recurring, small purchases | Low (controls built-in) |
| Demand Draft | 1–2 days | Government payments | Low |
Completing the example: On April 9 (within 30-day window), the AP system proposes payment for PO #2024-IT-0312. The CFO approves. ₹12,40,000 (20 × ₹62,000) is transferred via RTGS to Dell India. A remittance advice is emailed to Dell. SAP automatically clears the AP liability and posts the bank entry. The AP cycle is complete.
What Happens When AP Goes Wrong — and Right
These real-world cases illustrate the consequences of AP process failures — and the rewards of doing it well.
The Accounts Payable Fraud at Koss Corporation (Wisconsin, USA)
Between 2004 and 2009, Sue Sachdeva — Vice President of Finance at Koss Corporation, a headphone manufacturer — embezzled over $34 million (later revised estimates suggest up to $14 million in AP-related fraud) by exploiting weaknesses in the AP process. She used her access to create fictitious vendor accounts, approve her own payments, and wire money to credit card companies to cover personal luxury purchases including furs, jewellery, and designer clothing.
The AP failure? There was no segregation of duties. The same person who could create vendors could also approve and execute payments. No three-way match was enforced. No second signatory was required. The external auditor (Grant Thornton) also failed to detect the fraud.
How Unilever Used AP Strategically to Save Millions
Unilever, the FMCG giant, runs one of the world's most sophisticated AP programmes. Rather than treating AP as simply "paying bills," Unilever uses dynamic discounting — a technique where suppliers can choose to receive early payment in exchange for offering Unilever a discount.
During a period of tight credit markets, many of Unilever's 70,000+ suppliers were struggling with cash flow. Unilever deployed a supply chain finance platform allowing suppliers to request early payment at any point — receiving their money within 2 days instead of the standard 60-day terms — in exchange for a small discount (typically 0.5% to 2%).
The Municipality That Paid the Same Invoices Twice
A municipal corporation in a large Indian city (name withheld per audit report) discovered during a CAG (Comptroller and Auditor General) audit that it had made duplicate payments totalling ₹4.7 crore across 340 vendor invoices over 3 years. The cause: invoices were being processed by two different departments (Public Works and Finance) which maintained separate records. When a vendor submitted the same invoice to both departments, both paid it.
There was no centralised AP system. No PO numbers were being used. No systematic duplicate-check was performed. Vendors discovered the error — many honestly returned the duplicate payment; some did not.
AP Process Across Different Industries
The AP cycle looks slightly different depending on the industry. Here are three industry-specific walkthroughs.
Example 1: Manufacturing Company (Auto Parts)
Tata AutoComp Systems needs steel sheets for producing door panels.
- PR: Production planning team raises PR for 50 tonnes of cold-rolled steel, ₹80,000/tonne, delivery in 10 days.
- PO: Procurement sends PO to JSW Steel with specifications: grade IS:513, 50 tonnes, ₹78,500/tonne (negotiated), Net 45 payment terms.
- GRN: Steel arrives at warehouse. Quality inspector takes samples, performs thickness and hardness tests, and signs off GRN for 50 tonnes — Grade A, No rejections.
- Invoice Processing: JSW sends e-invoice through GSTN portal. AP team runs three-way match on SAP — passes. Invoice posted to GL.
- Payment: On day 40 (within Net 45), RTGS payment of ₹39,25,000 (50 × ₹78,500) is made. TDS @0.1% deducted under Section 194Q.
Total cycle time: 10 days (delivery) + 3 days (GRN + invoice) + 40 days (payment) = 53 days from PR to payment closed.
Example 2: Retail Chain (FMCG)
BigMart (hypothetical retail chain) replenishes its dairy shelves every week.
- PR: Store manager's system auto-generates PR when yoghurt stock falls below minimum level (automated via ERP).
- PO: System auto-generates a blanket PO to Mother Dairy for weekly deliveries — no human intervention needed for standard items.
- GRN: Deliveries arrive Monday morning. Store staff scan each crate barcode — system auto-creates GRN and checks for expiry dates and temperature compliance (cold chain).
- Invoice Processing: Mother Dairy uploads consolidated weekly invoice on BigMart's vendor portal. System auto-matches.
- Payment: BigMart pays all FMCG vendors on a standard weekly payment run every Friday.
Key feature: This entire cycle from PR to payment proposal is fully automated for standard SKUs — zero human touchpoints unless an exception is flagged.
Example 3: IT Services Company (Software Subscription)
A consulting firm subscribes to Salesforce CRM for 200 users.
- PR: IT Director submits PR for Salesforce Enterprise license renewal — $48,000/year, paid annually.
- PO: Since this is a recurring software subscription, a contract PO is issued covering the annual term.
- GRN equivalent: No physical goods — the IT department signs a Service Acceptance Certificate confirming the licenses are active and accessible.
- Invoice Processing: Salesforce sends annual invoice. AP team verifies user count (200 matches contract), price per user ($240 × 200 = $48,000 matches PO). Invoice approved.
- Payment: Wire transfer in USD to Salesforce's US bank account. Foreign currency revaluation entry posted.
Special consideration: The company must prepay for the full year upfront (Salesforce's standard terms) but expense it monthly — requiring a prepaid expenses accounting entry amortised over 12 months.
AP KPIs — Measuring Process Health
| KPI | Formula | Industry Benchmark | Good / Bad |
|---|---|---|---|
| Cost per invoice | Total AP cost ÷ Invoices processed | $2–$10 (automated) | Lower = better |
| Invoice cycle time | Invoice receipt to payment (days) | 5–8 days (automated) | Faster = better |
| Straight-through rate | % invoices with no exceptions | 70–85% | Higher = better |
| Duplicate invoice rate | Duplicate invoices ÷ Total invoices | <0.1% | Lower = better |
| On-time payment rate | Invoices paid by due date ÷ Total | >95% | Higher = better |
| Early discount captured | Discounts taken ÷ Discounts available | >80% | Higher = better |
| Days Payable Outstanding | (AP balance ÷ COGS) × 365 | 30–60 days | Context dependent |
Quiz — Accounts Payable Process
10 questions · Answers shown on click · All questions based on content above
Frequently Asked Questions
Everything beginners and practitioners commonly ask about the AP process.