Three-way match in accounts payable, explained
A three-way match checks a supplier invoice against the purchase order and the receiving record before the invoice is paid. If quantities, prices and terms agree within tolerance, the invoice can be approved; if they don't, it becomes an exception for a person to resolve. Here's how it works, where it breaks down, and how AP automation tools handle it.
Key points
- The three documents
- The purchase order (what was ordered), the receiving record or goods received note (what arrived) and the supplier invoice (what you're asked to pay).
- What gets compared
- Supplier, item or service, quantity, unit price and terms, usually line by line, within tolerances the company sets.
- Why it matters
- It stops payment for goods that weren't ordered or didn't arrive, and catches price and quantity differences before cash goes out.
- Two-way vs four-way
- A two-way match compares only the invoice and the PO. A four-way match adds an inspection or acceptance record to the three.
What a three-way match compares
Each document is created by a different part of the business, which is what gives the match its value as a control: purchasing commits to the order, the receiving team confirms delivery, and the supplier bills.
| Document | Created by | What it shows | Fields usually matched |
|---|---|---|---|
| Purchase order (PO) | Purchasing, after approval | What the company agreed to buy and at what price | Supplier, item, quantity ordered, unit price, terms |
| Receiving record (goods received note) | Receiving or the requester | What actually arrived, and when | PO number, item, quantity received, date |
| Supplier invoice | The supplier | What the supplier is billing | PO number, item, quantity billed, unit price, total, terms |
How the three-way match works
The invoice arrives
AP captures the invoice and identifies the PO it relates to, from a PO number on the invoice or by supplier and line details.
Match to the PO
Supplier, items and unit prices on the invoice are compared with the PO lines.
Match to the receipt
Quantities billed are compared with quantities received to date, so you only pay for what arrived.
Apply tolerances
Small differences within the company's tolerance (for example, a rounding difference or an agreed freight charge) can pass automatically.
Approve or raise an exception
Matched invoices move to payment on their terms. Differences go to purchasing, the requester or the supplier to resolve.
Two-way, three-way and four-way matching
| Match | Documents | Typically used for |
|---|---|---|
| Two-way | Invoice and PO | Services and items where a separate receiving step isn't recorded |
| Three-way | Invoice, PO and receiving record | Physical goods, where delivery can be confirmed |
| Four-way | Invoice, PO, receiving record and inspection or acceptance record | Goods that must pass quality inspection before they're accepted |
Many companies use more than one level, set by supplier, category or amount. Invoices with no PO at all (rent, utilities, many professional services) are approved through a separate workflow rather than matched.
Tolerances and exceptions
Tolerances decide how strict the match is. They are usually set as a percentage, an amount or both, separately for price and quantity, and sometimes by supplier or category. Too tight and AP spends its time on trivial exceptions; too loose and the control stops catching anything.
- Price variance
- The invoice unit price differs from the PO. Resolve with purchasing: update the PO if the new price was agreed, or ask the supplier for a corrected invoice.
- Quantity variance
- More is billed than was received. Hold the excess until the receipt is recorded or the supplier issues a credit.
- Partial receipt
- Only part of the order has arrived. Pay for what's received, or hold the invoice, depending on policy.
- No receipt recorded
- Goods may have arrived without anyone entering the receipt. Confirm with the requester before paying.
- Duplicate invoice
- The same invoice submitted twice, sometimes with a slightly different number. Check supplier, amount and date together.
Why the three-way match is a control
The three-way match works because the people who order, receive and pay are different. If one person can create the PO, record the receipt and approve the invoice, the match proves very little. Keep those duties separate in your systems, restrict who can edit POs after approval, and review overrides of match exceptions.
Keep the record, too: a documented match with its exceptions and who approved them is evidence you can show a reviewer or auditor, not just a step in the workflow.
How AP automation and AI handle matching
AP automation software captures invoice data, matches it to POs and receipts in the ERP, applies your tolerances and routes exceptions to the right person. Newer products use AI to read invoices in varied formats, match line descriptions that don't exactly agree with PO wording, and explain why an invoice failed to match. What each vendor documents:
| Tool | What its documentation says |
|---|---|
| Coupa AP AutomationAP & invoices | Two-way and three-way PO matching with customer-set tolerances and auto-approval for invoices that match |
| AvidXchangeAP & invoices | AI PO Matching Agent that matches invoice line items to purchase-order header and line data and flags discrepancies |
| TipaltiAP & invoices | PO Matching Agent matches bills to purchase orders by comparing line descriptions |
| YoozAP & invoices | Line-level PO matching that compares invoice lines with purchase orders and surfaces exceptions for review |
| MediusAP & invoices | SmartFlow suggests coding, tax and approver values for non-PO invoices based on earlier invoices from the same supplier |
| AppZenAP & invoices | Autonomous AP captures invoices in any format or language, assigns GL codes and allocations to non-PO invoices, and matches invoice lines to POs, flagging exceptions and possible duplicates |
| BaswareAP & invoices | SmartCoding uses machine learning to suggest coding for non-PO invoices |
| Vic.aiAP & invoices | Purchase-order matching and role-based approval routing |
| StampliAP & invoices | Learns approval routing and purchase-order matching patterns |
| RampAP & invoices | AP policy review agent (beta) checks bills against an editable AP Review Policy using contracts, purchase orders, budgets and supporting documents |
Check whether a tool matches at header level or line level, whether it reads goods receipts from your ERP, and how it records who approved an exception. Compare AP tools on SOC 2 and data use in AI invoice automation and AP software, or directly in Tipalti vs Ramp and Ramp vs BILL.
Three-way match: questions
- What is a three-way match?
- An accounts payable control that compares a supplier invoice with the purchase order and the receiving record before payment. The invoice is approved when supplier, items, quantities and prices agree within the company's tolerances.
- What is the difference between a two-way and a three-way match?
- A two-way match compares the invoice with the purchase order only. A three-way match also checks the receiving record, so the company pays only for goods that arrived.
- What is a four-way match?
- A three-way match plus an inspection or acceptance record, used when goods must pass quality checks before the company accepts them.
- Can three-way matching be automated?
- Yes. AP automation tools pull PO and receipt data from the ERP, match invoice lines to them, apply tolerances and send only exceptions to people. Several now use AI to read invoices and match line descriptions; see AI invoice automation and AP software.
- What happens when an invoice doesn't match?
- It becomes an exception. AP routes it to purchasing, the requester or the supplier to resolve the price or quantity difference, record a missing receipt, or obtain a corrected invoice or credit note before payment.