What Is Three-Way Matching in Accounts Payable?
Three-way matching is an accounts payable control that checks a supplier's invoice against two other records before releasing payment: the purchase order that authorised the purchase, and the goods received note (or delivery or service confirmation) that proves it actually arrived. Only when all three agree does the invoice move forward for approval.
It sits alongside two other common matching methods:
- Two-way matching: invoice against purchase order only.
- Three-way matching: invoice against purchase order against goods received note.
- Four-way matching: adds a quality or inspection report on top of three-way matching.
Three-way matching is the standard choice wherever a business needs proof that what was billed is also what was delivered.
Why Does Three-Way Matching Matter in Accounts Payable?
Three-way matching matters because it closes the gap between what a supplier says was delivered and what a business actually received. Without it, accounts payable teams are effectively trusting the invoice on its own.
The process directly protects against:
- Overpayment: being billed for a higher quantity or price than agreed.
- Duplicate payment: the same invoice or PO being paid more than once.
- Fraudulent or unauthorised invoices: payment requests with no corresponding PO.
- Paying for undelivered goods: invoices for items that were short-shipped, damaged, or never arrived.
It also creates a clean audit trail, since every payment can be traced back to an approved PO, a confirmed delivery, and a matched invoice, something auditors and finance leadership both rely on.
How Does Three-Way Matching Work?
Three documents are compared during the process:
| Document | Created by | Confirms |
|---|---|---|
| Purchase order (PO) | Buyer or procurement team | What was ordered, at what price and quantity |
| Goods received note (GRN) | Receiving or warehouse team | What actually arrived, and in what condition |
| Supplier invoice | Vendor or supplier | What the supplier is billing for |
Step-by-step process:
- Generate a purchase order. Procurement raises a PO in their purchase order software and sends it to the vendor, setting out items, quantities, and agreed prices. This becomes the baseline for everything that follows.
- Receive the goods or services. When the delivery arrives, the receiving team checks it against the PO and logs a goods received note, recording quantity and condition.
- Receive the invoice. The supplier submits an invoice for the goods or services delivered.
- Review the documents. The accounts payable team compares the PO, GRN, and invoice side by side, checking that quantities, unit prices, and totals align.
- Resolve any discrepancies. If something does not match, a price difference, a short delivery, an unexpected charge, the invoice is placed on hold until it is investigated and resolved with the supplier or internal team.
- Approve payment. Once all three documents agree within acceptable tolerance, the invoice is approved and scheduled for payment.
Three-Way Matching Example
Consider a business ordering 100 laptops at £1,085 each, for a total purchase order value of £108,500.
- The purchase order confirms 100 laptops at £1,085 each.
- The goods received note, logged by the warehouse team, confirms all 100 laptops arrived in good condition.
- The supplier invoice bills the company £108,500 for 100 laptops.
Because all three documents agree, the accounts payable team clears the invoice for payment. If the goods received note had instead shown only 90 laptops delivered, the mismatch would be caught immediately: the invoice would be held, and the AP team would raise the discrepancy with the supplier before any payment was released, rather than discovering the shortfall after the money had already gone out.
When Should You Use Three-Way Matching?
Three-way matching is most valuable wherever delivery risk or purchase value is high enough to justify the extra verification step. Common scenarios include:
- Physical goods purchases: inventory, equipment, raw materials, or anything that can be counted and inspected on arrival.
- High-value or one-off purchases: where an error would be costly and the item is not a familiar, recurring cost.
- Manufacturing, healthcare, and pharmaceutical businesses: sectors where receiving the correct materials in the correct quantity is a compliance issue as well as a financial one.
- Businesses managing multiple suppliers at scale: where manual trust-based approval is not sustainable as invoice volume grows.
What Is 2-Way Matching, and When Is It Enough?
Two-way matching is the simpler control: it compares the supplier invoice against the purchase order alone, with no goods received note. If the billed items, quantities, and prices match the PO, the invoice is approved for payment.
Because it skips the delivery-confirmation step, 2-way matching is best suited to purchases where there is nothing physical to receive, or where delivery risk is low:
- Recurring, predictable costs such as a monthly software subscription.
- Services rather than physical goods, where no GRN would ever be raised.
- Low-value purchases where the cost of a full three-way check outweighs the risk.
The trade-off is assurance: 2-way matching confirms you were billed what you agreed to pay, but not that anything was actually delivered. For that reason, many finance teams use two-way matching for services and low-risk spend, and reserve three-way matching for physical goods and higher-value orders.
2-Way vs 3-Way vs 4-Way Matching in Accounts Payable
| Method | Documents compared | Best for |
|---|---|---|
| 2-way matching | Purchase order and invoice | Low-value, recurring, or service-based purchases with minimal delivery risk |
| 3-way matching | Purchase order, goods received note, and invoice | Physical goods, higher-value purchases, and anywhere proof of delivery matters |
| 4-way matching | Purchase order, goods received note, invoice, and inspection or quality report | Regulated or quality-critical industries, such as manufacturing or healthcare |
The right method depends on risk, not just value. A recurring low-cost purchase with a trusted supplier may only need a two-way match, while a one-off, high-value, or physically delivered order usually warrants the extra step of a three-way match. Four-way matching adds further assurance where quality or compliance checks are non-negotiable.
What Documents Are Needed for Three-Way Matching?
Three-way matching depends on having all three source documents complete, accurate, and available at the point of invoice review:
- Purchase order: itemised, with agreed quantities, unit prices, and a unique PO number.
- Goods received note: logged as soon as a delivery arrives, noting quantity, condition, and date received.
- Supplier invoice: referencing the correct PO number, with matching item descriptions, quantities, and pricing.
Keeping these documents digitised and centrally accessible, rather than scattered across email threads, paper files, and spreadsheets, is what makes the matching step fast rather than a bottleneck.
Challenges of Manual Three-Way Matching
Handled manually, three-way matching is one of the more time-consuming parts of accounts payable. Common pain points include:
- Document hunting. Tracking down the right PO, GRN, and invoice across email, paper, and shared drives before a comparison can even begin.
- Line-by-line checking. Larger orders with many line items make manual comparison slow and prone to human error.
- Delayed resolution. When a mismatch is found, resolving it often means emails, phone calls, or chasing down a warehouse team, all of which delay payment.
- Scaling problems. As invoice volume grows, manual matching becomes a genuine bottleneck, risking late payments, damaged supplier relationships, and missed early-payment discounts.
How to Automate Three-Way Matching in Accounts Payable
Automated three-way matching removes the manual document hunt and line-by-line comparison, matching purchase orders, goods received notes, and invoices as soon as all three are available. Software such as Zahara's accounts payable automation software handles both two-way and three-way matching, routing only genuine exceptions to a person.
Typical benefits of automation include:
- Faster approvals: matched invoices move straight to payment without manual review.
- Exception-based workflow: only genuine discrepancies are routed to a person, rather than every invoice.
- Fewer errors: automated tolerance rules catch mismatches consistently, without relying on manual attention to detail.
- A complete audit trail: every match, exception, and approval is logged automatically.
Before automating, it is worth assessing whether your current PO and receiving process is consistent enough to match against. Automation works best once purchasing and receiving data is already structured and digitised, rather than being introduced to paper over a disorganised process.
Conclusion
Three-way matching in accounts payable is one of the simplest and most effective controls a finance team can put in place: it ensures a business only pays for what was ordered and what actually arrived. Two-way matching offers a lighter-touch alternative for services and low-risk spend. Done manually, either method is reliable but slow to scale. Automated, matching becomes a fast, low-friction safeguard that protects cash flow and supplier relationships as invoice volume grows.
Book a demo to see how Zahara helps finance teams automate matching and invoice approval without disrupting existing processes.