Purchase Order Matching

Purchase Order Matching is the process of verifying a vendor invoice against the purchase order and goods receipt, using 2-way or 3-way matching, to confirm the company pays only for what was ordered and received. Two-way matching compares the invoice to the purchase order. Three-way matching adds the goods receipt, which is what catches short deliveries before payment.

Category: Accounts Payable Automation SoftwareBest Accounts Payable Automation Software

Your AP team approved a vendor invoice for $84,000 last month. The purchase order was for $76,000. Nobody caught the discrepancy before payment. The difference turned out to be a vendor billing error, which the vendor acknowledged and corrected, but not before the payment cleared. Two-way matching would have held it. Purchase order matching is the process of comparing a vendor invoice against the purchase order that authorized the spend and, for goods, against the receiving document that confirms delivery. The point is to confirm that what you're billed for matches what you authorized and what you received before any payment goes out. When a match succeeds, the invoice moves on to approval and payment. When it fails, the invoice is held until the discrepancy is resolved. In organizations with formal procurement processes, PO matching is the primary financial control over non-payroll spend. It enforces budget discipline by allowing invoices to be paid only against authorized purchase orders, and it catches billing errors and duplicate invoices before money leaves the company rather than after. How well PO matching works as a control depends on how widely it is applied, what tolerances are set, and how exceptions are handled when matches fail.

How purchase order matching works

Two-way matching compares the vendor invoice to the purchase order. The check is whether the invoice amount, vendor, and line items correspond to what was authorized. Two-way matching suits service invoices where there is no physical delivery to confirm: consulting engagements, software subscriptions, maintenance contracts. Three-way matching adds the goods receipt or receiving document to the comparison. The invoice is checked against both the PO (was this authorized?) and the receipt (was this actually delivered?). Three-way matching is the standard for procurement of physical goods. It prevents payment for items that were ordered and invoiced but not yet received, and it catches invoices for quantities above what was delivered. Four-way matching adds an inspection or quality record as a fourth document, confirming that goods arrived in acceptable condition as well as that they arrived. Four-way matching is used in manufacturing and regulated industries where quality documentation is part of the acceptance process. For each matching type, tolerances define how much variance is acceptable before the system flags an exception. A 2% quantity tolerance on a three-way match means an invoice for 102 units against a PO for 100 units and a receipt for 100 units will pass. An invoice for 115 units won't. Set tolerances based on the variance you actually expect and accept in operations, not wide enough to avoid exceptions.

Match tolerance settings, what happens when matches fail

Match tolerance configuration is a policy decision with financial risk at both ends of the range. Set tolerances too tight and the exception rate climbs, creating AP bottlenecks where invoices pile up waiting for discrepancies to be investigated, many of which turn out to be rounding differences or legitimate price adjustments. Set tolerances too wide and the matching control stops working: an invoice 10% higher than the PO passes automatically, which removes the protection matching was supposed to provide. Most AP systems let you set tolerances as a percentage or an absolute dollar amount, and configure them differently by vendor category, commodity type, or dollar threshold. A $50,000 invoice getting through on a 5% tolerance means $2,500 in uninvestigated variance. The same 5% tolerance on a $200 office supply invoice means $10, a reasonable rounding buffer. When a match fails, the invoice goes into an exception queue. Someone has to investigate: contact the vendor for a corrected invoice, ask the receiving team to confirm what was actually received, or request a PO amendment from the requestor. Each of those steps takes time and involves more than one party. High exception rates slow down payment, and they also pull AP staff away from processing into resolution work and create payment delays that damage supplier relationships. The AP automation savings calculator can help you estimate what that exception handling costs.

How platforms handle it

In AP automation platforms, PO matching runs automatically at the point of invoice processing. The system compares invoice fields to PO fields and receipt fields, applies tolerance rules, and classifies the invoice as matched, matched within tolerance, or exception. Invoices that match straight through go on to the approval and payment workflow automatically. Exceptions are routed to a resolution owner, and the right owner is not always obvious. If the discrepancy is a quantity mismatch, the owner is probably the receiving team. If it's a price discrepancy, it may be procurement. If the invoice is for goods that haven't been received yet, the resolution is simply to wait. AP platforms that handle exceptions well identify the discrepancy type, route it to the correct resolver, and track resolution status. Platforms that handle exceptions poorly put every exception into a generic queue where AP staff have to investigate and route each one by hand. When evaluating AP platforms for matching, ask: how are exceptions categorized, who are they routed to, and what does the resolution workflow look like? A demo will show the matched invoice path. The operational value is in the exception path and how quickly it gets to resolution.

Questions to ask

What percentage of our invoices are matched against a PO, and what percentage arrive with no PO number and need non-PO or exception handling?
Are our tolerance thresholds set based on documented policy, and have they been reviewed in the past 12 months to ensure they still reflect acceptable variance?
When a match exception occurs, what is the escalation path: who is responsible for resolution, and what is the target resolution time?
Do we require three-way matching for all goods purchases, or are some goods categories matched only on two-way, and is that intentional?
How does our AP platform handle invoices that arrive before a receipt is recorded? Are they held, parked, or processed?
What is our current exception rate, and do we track it by exception type to identify systemic causes versus isolated errors?

Common mistakes

Setting match tolerances wide to avoid exceptions is the most direct way to neutralize PO matching as a financial control. If every invoice within 10% of the PO amount passes automatically, vendors with billing errors (or vendors testing what will get caught) can keep overbilling within that range. The tolerance should reflect acceptable operational variance, not whatever level keeps the exception queue manageable. If the exception rate is too high, fix the upstream causes, such as weak PO discipline, receiving processes, or supplier enablement, rather than widening the tolerance window. Having no clear escalation path for match exceptions over a dollar threshold is a control gap that large invoice populations expose. An exception on a $500 invoice can sit in a queue for a few days without much financial risk. An exception on a $500,000 invoice should go straight to senior AP management or finance leadership. Most AP configurations treat all exceptions the same regardless of dollar amount. Escalation rules by dollar threshold, which route large-dollar exceptions to senior staff with shorter resolution windows, are good practice that many organizations haven't put in place.

Comparing AP automation

AP tools separate on what happens to the exceptions: the invoices that do not match a PO, arrive without one, or need a second approver. Once purchase order matching is settled as a requirement, read the Accounts Payable Automation Software category guide for how the market splits, then weigh the Stampli profile against the Tipalti profile on that requirement rather than on the feature list. Our Tipalti pricing breakdown records what the vendor publishes and what is quote-based. The BILL against Stampli comparison sets two of them side by side on the same criteria. Before you book demos, put your own numbers through the AP automation savings calculator so the business case is written down before a vendor writes it for you.

Purchase Order Matching questions

How is purchase order matching different from three-way match?

Three-way match is a specific type of purchase order matching that compares three documents: the purchase order, the vendor invoice, and the goods receipt. Purchase order matching is the broader category that includes two-way match (PO and invoice only), three-way match, and four-way match. Three-way match is the most commonly referenced standard for goods purchases, which is why people often use the terms interchangeably. When someone says 'PO matching' without specifying the type, they usually mean three-way match for goods procurement.

What should we do when an invoice arrives before the PO is created?

An invoice that arrives before a PO exists (sometimes called a maverick or after-the-fact purchase) means a purchase was made outside the approved procurement process. The right response is not to create a PO retroactively just to clear the invoice, though that is common practice. Instead, find out why the purchase was made without a PO, require approval from the requestor's manager before creating the retroactive PO, and track after-the-fact POs by department to spot patterns. Routinely allowing after-the-fact POs signals that the procurement policy isn't being followed and that PO matching is not actually controlling spend.

Can we apply PO matching to services invoices, or only goods?

PO matching applies to services invoices, but usually in two-way form: matching the invoice to the PO without a receiving document, since services don't produce a goods receipt. Some organizations use a service entry sheet or time-and-materials acceptance record in place of the receipt, which allows three-way matching for services. This is most common for large consulting or staffing engagements where deliverables or hours are tracked against the contract. For recurring services with fixed monthly amounts, such as software subscriptions and maintenance contracts, two-way matching against a blanket PO is standard.

ACH Payment, AP Aging Report, and Approval Workflow come up in the same workflow as purchase order matching, and the rest of the AP automation cluster is indexed in the finance operations glossary.