Three-Way Matching Explained: Purchase Order, Goods Receipt and Invoice
Three-way matching checks a purchase order, a goods receipt and a supplier invoice against each other before you pay. Here is how it works in practice.
Most accounts payable teams describe their job as "paying invoices". The more accurate description is deciding which invoices deserve to be paid. Three-way matching is the control that makes that decision defensible, and it is the single cheapest way to stop overbilling, duplicate payments and invoice fraud before money leaves the building.
What three-way matching is
Three-way matching compares three documents before an invoice is approved for payment:
- The purchase order, which records what you agreed to buy and at what price.
- The goods receipt, also called a goods received note or GRN, which records what actually arrived.
- The supplier invoice, which records what you are being billed for.
If all three agree on quantity and price, the invoice is released. If any of them disagrees beyond an agreed tolerance, the invoice is held as an exception and a human looks at it. That is the whole idea. The value is not in the comparison itself but in the fact that no single person can create all three documents.
The three-way match compares what you ordered, what you received and what you were billed. Only an invoice that agrees with both of the other two documents is released for payment.
What each document actually proves
| Document | Created by | Answers the question |
|---|
| Purchase order | Procurement, after approval | Did we agree to buy this, at this price? |
| Goods receipt | Warehouse or the requesting team | Did we actually get it? |
| Supplier invoice | The supplier | What are they asking us to pay? |
Notice that the three documents originate in three different places. That separation is the control. An invoice on its own proves only that somebody sent you a bill.
Two-way, three-way and four-way matching
The number in the name is just the number of documents being compared.
- Two-way matching compares the purchase order and the invoice. It is appropriate for services and subscriptions where there is nothing to physically receive.
- Three-way matching adds the goods receipt. This is the default for physical goods.
- Four-way matching adds an inspection or quality certificate. It is used where acceptance is conditional, for example in manufacturing, pharmaceuticals and construction.
Applying three-way matching to a software subscription is a common configuration mistake. There is no goods receipt to create, so every invoice becomes an exception and the team learns to click through exceptions without reading them, which defeats the control everywhere else.
Tolerances: the part everyone gets wrong
Exact matching sounds rigorous and is unworkable in practice. Freight is added after the order, currency moves between order and invoice, and suppliers round differently. Without tolerances your exception queue fills with differences of a few cents and the genuinely wrong invoices hide among them.
A workable starting point:
| Variance type | Typical tolerance | Reasoning |
|---|
| Unit price | Lower of 2 percent or a small fixed amount | Absorbs rounding and small currency movement |
| Quantity, under delivery | 0 percent | Never pay for what did not arrive |
| Quantity, over delivery | 0 to 5 percent by category | Bulk and commodity items often ship slightly over |
| Total invoice value | A small absolute floor | Stops one cent differences creating work |
Two rules matter more than the numbers you pick. Tolerances should be asymmetric, because being under delivered and being over billed are not equally acceptable. And they should be percentage based with an absolute cap, so that 2 percent of a very large order does not quietly authorise a large amount.
When a match fails
A failed match is information, not an error. The useful question is which of the three documents is wrong.
- Price mismatch usually means the agreed price changed without the purchase order being updated, or the supplier billed list price instead of contract price.
- Quantity mismatch usually means a partial delivery, a receipt that was never entered, or goods that were returned after receipt.
- No purchase order at all means somebody bought something outside the process. This is maverick spend, and the invoice is the first time finance hears about it. The fix is upstream, in the purchase order approval workflow.
Track the reasons. If most exceptions are price mismatches on one supplier, the fix is a contract conversation, not more work in accounts payable. If most are missing receipts, the fix is in the warehouse. The exception report is a diagnostic tool for the rest of the business.
Why it is worth the effort
Three-way matching addresses several risks at once:
- Duplicate payment. A duplicate invoice cannot consume the same receipt twice.
- Overbilling. Quantity and price are checked against what was agreed and what arrived, not against what the supplier asserts.
- Fictitious invoices. An invoice from a fake supplier has no purchase order and no receipt behind it.
- Accurate accruals. Receipts without invoices are exactly the balance you need at period end. See our guide to goods received not invoiced.
Making it work without drowning in manual review
The control only survives if the routine cases clear themselves. In practice that means:
- Capture receipts at the point of delivery, not in a weekly batch. A receipt entered a week late guarantees an exception for every invoice that arrives first.
- Let invoices reference purchase order lines, not just the order header, so partial deliveries match cleanly.
- Match automatically and escalate by exception. Humans should see the 5 percent that fail, not the 95 percent that pass.
- Re-run the match when anything changes. A reversal or a late receipt can turn a matched invoice back into an exception, and the system should notice rather than waiting for a person to.
- Use structured invoices where you can. Extracting line items from a PDF is guesswork. Structured formats remove the guessing, which is one of the practical arguments for e-invoicing.
Common questions
Is three-way matching a legal requirement?
No, but it is close to universal in external audit expectations for organisations of any size, and auditors will test it. It also underpins the completeness of your period end accruals, which is a reporting requirement.
What if the supplier invoices before delivering?
The invoice sits unmatched until the goods arrive. That is the correct outcome. Advance payments should run through a separate prepayment process with its own approval, not through the matching queue.
Should services use three-way matching?
Generally no. Use two-way matching against the purchase order, or a milestone or timesheet approval where the deliverable is effort. Forcing a goods receipt for services creates a meaningless document that somebody has to invent.
How high should our first-pass match rate be?
Mature accounts payable operations typically clear most invoices without human intervention. If your rate is much lower, the cause is usually stale purchase order pricing or late receipt entry rather than anything wrong with the matching rules themselves.
The short version
Three-way matching is not paperwork. It is the mechanism that turns three independently created records into evidence that a payment is genuinely owed. Get the tolerances sensible, capture receipts promptly, automate the routine cases, and read your exception reasons as a diagnostic on the rest of the purchasing process.