What is three-way matching? How to match supplier invoices

Three-way matching is a check made before a supplier's invoice is paid. The invoice is compared with two other documents: the purchase order, to confirm the price is the price that was agreed, and the goods received note, to confirm the quantity is the quantity that arrived. If the three agree, within limits the business has set, the invoice goes forward for approval and payment. If they do not, it is held until someone resolves the difference. It is an accounting control, not a legal requirement.

How is it different from two-way matching?

Microsoft's documentation, which calls the goods received note a product receipt, describes the levels plainly. Two-way matching compares the price on the invoice with the price on the purchase order. Three-way matching does that and also matches the quantity on the invoice to the quantity on the receipts. The third document catches an invoice for goods that were ordered and never arrived, or arrived short, which two-way matching cannot see.

What is a matching tolerance?

A business can set a tolerance, as a percentage or an amount, and a difference inside it passes. Microsoft's own example is an order for 1,000 batteries at 1.00 each with a five per cent tolerance on unit price: an invoice at 1.05 is acceptable and an invoice at 1.10 is not. A difference outside the tolerance is a matching discrepancy, and the invoice waits until it is resolved or someone with the authority approves it.

How do you three-way match a supplier invoice?

In a wholesale or distribution business the invoice usually arrives by email as a PDF, and a purchase ledger clerk takes it through eight steps.

1. Capture. Enter the supplier, invoice number, your order number, each line and the totals, and check the invoice has not been entered before.

2. Match to the purchase order, for price. No order number on the invoice means a search, and no order at all means finding out who bought it.

3. Match to the goods received note, for quantity. Billed for 40 cases and received 36, the invoice is held.

4. Apply the tolerance. A few pence of rounding should not stop an invoice; a price rise nobody agreed should. The tolerance is your rule, set by whoever runs finance, and written down.

5. Settle what is held. A short delivery goes to the supplier for a credit note, a price difference to the buyer, a missing goods received note to the warehouse.

6. Code and queue. Stock or overhead, the right nominal code and the VAT as the invoice shows it, then into the approval queue.

7. Approve and pay. An authorised person approves, and the invoice joins the payment run on its due date.

8. File. HMRC treats the VAT invoice as the primary evidence for reclaiming input tax and, as a rule, requires VAT records to be kept for at least six years. Where a scanned image holds all the VAT detail, HMRC does not need the paper kept, unless you need it for another purpose.

In wholesale the match protects margin, since a few pence on a unit price is repeated across thousands of units. In manufacturing and on a construction contractor's sites it keeps job costs honest where materials go to places the office never sees.

Why do invoices fail the match?

Easy invoices are quick; the day goes on the rest. The invoice quotes no order number. The delivery was split in two and only the first half was booked in. The supplier's price list changed in March and the order was raised from the old one. The goods arrived on Thursday and the warehouse has not entered the receipt; Microsoft's example has that case, a receipt not yet posted and a failed quantity match. Each is settled by a message to the buyer, the warehouse or the supplier. Five habits cut the chasing:

• Order numbers. Tell suppliers an invoice without your order number will be returned, and buyers that nothing is bought without one.

• Booking in on the day, against the order, with the quantity counted and not copied from the delivery note. If goods-in books a week's deliveries on Friday, every invoice that week fails its match.

• One list of held invoices: what is wrong, who it is with, since when. Where no payment date has been agreed, the law treats payment as late 30 days after you get the invoice, or after the goods are delivered or the service provided, if this is later.

• One accounts address for every supplier's invoices.

• Supplier statements, read. A statement checked against your ledger finds the invoice you never received before the supplier stops the account.

What is three-way matching confused with?

• Invoice approval. A manager approving an invoice is a person vouching for it; a match is the documents vouching for each other. A system can be set to require approval before an invoice that fails the match is posted.

• A fraud check. Matching confirms what is owed, and says nothing about who to pay. The Take Five to Stop Fraud campaign advises businesses to question any change in payment information and confirm it directly with the supplier using the contact details already on file.

Which parts can an AI worker take on?

An AI worker can read each invoice and credit note as it arrives in the accounts mailbox, check for a duplicate, find the order and the receipt, and compare the lines within your tolerances. It can code the lines from the order and from how that supplier was coded before, and queue the invoices that match for approval with the order and receipt beside them. For those that do not, it can state the difference line by line and send the question, in wording you approved, to the warehouse, the buyer or the supplier. It can keep the list of what is held and check supplier statements against the ledger. The role is on our page for purchase invoice processing, and the supplier records it relies on are covered by supplier onboarding.

What stays with a person?

Approval of every invoice stays with your people: approval is the control, and an AI worker that matched and approved would be marking its own work. An AI worker never moves money; the payment run is approved and released by your own people. So is any decision to pay an invoice that has failed the match, to accept a price rise or a part delivery, any dispute with a supplier, each new supplier account, and the tolerances themselves, which are your policy. VAT treatment that looks wrong goes to whoever does your VAT return. A request to change a supplier's bank details is never acted on by the AI worker: it is passed to a named person to confirm with the supplier in the way your procedure says. The definitions here are from an accounting system maker's own documentation, as read on 3 October 2026.

For a business with a busy purchase ledger the worker would match invoices as they arrive and chase mismatches to an answer, and your people would approve every invoice and release every payment. If month end goes on queries, talk to our agent.