What is Three-Way Matching?

Three-way matching is an accounts payable control that verifies an invoice against two other documents before payment: the purchase order (PO) and the receiving document (also called a goods receipt). When all three documents agree, the invoice is approved for payment. When they don’t, the discrepancy triggers investigation.

The Three Documents

1. Purchase Order (PO)

The purchase order is your company’s official authorization to buy goods or services. It specifies:

• What you’re ordering (items, quantities)
• The agreed price
• Delivery terms and dates
• Payment terms
• Ship-to location

The PO represents what you intended to buy.

2. Receiving Document (Goods Receipt)

The receiving document confirms what actually arrived. It records:

• Items received
• Quantities received
• Condition of goods
• Date received
• Who received them

The receiving document represents what you actually got.

3. Invoice

The invoice is the vendor’s request for payment. It shows:

• Items billed
• Quantities billed
• Prices charged
• Payment terms
• Amount due

The invoice represents what the vendor wants to be paid for.

How Three-Way Matching Works

The matching process compares key fields across all three documents:

Perfect Match

When all three documents align, the invoice is approved for payment automatically (in automated systems) or flagged as ready for approval (in manual systems).

Mismatch Examples

Quantity mismatch: PO says 100, received 95, invoice says 100 - Don’t pay for 5 items you didn’t receive

Price mismatch: PO says $10/unit, invoice says $12/unit - Vendor may have applied wrong pricing

Item mismatch: PO says Widget A, invoice says Widget B - Wrong product billed, or wrong product shipped

Why Three-Way Matching Matters

Prevents Overpayment

Without matching, you might pay for: - Items never ordered - Items not received - Quantities higher than delivered - Prices higher than agreed

Catches Errors Early

Discrepancies surface before payment, not after. It’s much easier to resolve issues when you’re holding the money than after you’ve paid.

Deters Fraud

Three-way matching makes it harder to: - Pay fictitious vendors - Inflate invoices - Bill for undelivered goods - Collude with vendors

Creates Accountability

Each document comes from a different source: - PO: Purchasing department - Receipt: Receiving/warehouse - Invoice: Vendor

This separation of duties means no single person controls the entire process.

Two-Way vs. Three-Way Matching

Two-Way Matching

Compares only the PO and invoice. Faster but riskier—you might pay for goods never received.

Use two-way matching for: - Low-value purchases - Services (where there’s no physical receipt) - Trusted vendors with strong track records - Subscriptions and recurring charges

Three-Way Matching

Adds the receiving document. More thorough but requires more process.

Use three-way matching for: - High-value purchases - Physical goods - New or less-trusted vendors - Items with quality concerns

Four-Way Matching

Some organizations add a fourth document: inspection or quality verification. Common in manufacturing or when receiving specialized equipment.

Common Matching Challenges

No PO Exists

The most common issue. Someone ordered without a PO, or it’s a type of expense that doesn’t use POs.

Solutions: - Require POs for all purchases above a threshold - Create “blanket POs” for recurring needs - Implement a non-PO invoice workflow

Partial Shipments

Vendor ships in multiple deliveries, but sends one invoice.

Solutions: - Match to cumulative receipts - Request invoices per shipment - Track partial matches in your system

Services vs. Goods

Services don’t have physical receiving documents.

Solutions: - Use service confirmation instead of goods receipt - Require manager sign-off as “receipt” - Implement two-way matching for services

Price Variances

Minor price differences due to rounding, currency conversion, or minor adjustments.

Solutions: - Set tolerance thresholds (e.g., 1% or $10) - Auto-approve within tolerance - Flag larger variances for review

Timing Issues

Invoice arrives before goods, or receipt isn’t entered promptly.

Solutions: - Hold invoice until receipt is recorded - Improve receiving process compliance - Set up workflow notifications

Implementing Three-Way Matching

Manual Process

1. Receive invoice
2. Find matching PO
3. Find matching receiving document
4. Compare quantities and prices
5. Investigate discrepancies
6. Approve or reject

Works for low volumes but becomes unsustainable as you grow.

Automated Process

Modern AP systems automate matching:

1. Invoice is captured and data extracted
2. System finds matching PO by number
3. System finds matching receipts
4. Automatic comparison runs
5. Perfect matches auto-approve
6. Exceptions route to reviewers

Automation handles volume and catches discrepancies humans might miss.

Tolerance Thresholds

Most organizations don’t require perfect matches. Common thresholds:

Set thresholds based on your risk tolerance and transaction values.

Best Practices

Require POs

The most effective improvement is requiring purchase orders. Without a PO, you have nothing to match against.

Enter Receipts Promptly

Matching only works if receiving documents exist. Train receiving staff to enter receipts same-day.

Standardize Vendor Invoice Format

Ask vendors to include PO numbers prominently. Matching is faster when the PO reference is clear.

Review Exceptions Daily

Don’t let mismatches pile up. Address them while details are fresh.

Analyze Match Rates

Track your match rate (percentage that match on first pass). Low rates indicate process issues: - Frequent PO changes not communicated - Receiving delays - Vendor billing errors - Contract pricing not loaded correctly

Key Takeaways

• Three-way matching compares PO, receiving document, and invoice before payment
• It prevents overpayment, catches errors, and deters fraud
• Set tolerance thresholds to balance control with efficiency
• The process only works if POs exist and receipts are entered promptly
• Automation handles volume and improves accuracy

Want to ensure invoices arrive with PO references? See how BillerPlus captures invoice data at intake →