In the worked example below, we assume 0.1–0.5% of AP volume in duplicate payments — at €5M in spend that's €5,000–€25,000 per year leaking away unnecessarily. 3-way matching prevents this by automatically checking that invoice, purchase order, and goods receipt align. This article explains how it works, when you need it, and how Glimps configures it in Exact Online.
What is 3-way matching exactly?
3-way matching compares three documents before approving an invoice for payment:
- The purchase order (PO). What was ordered? Which items, how many, at what price?
- The goods receipt (GR). What was actually delivered? Which items, how many?
- The invoice. What is the supplier billing for? Which items, how many, at what price?
Only when all three are consistent — and within agreed tolerances — does the invoice auto-approve. Differences on any axis trigger an exception for human review.
2-way vs 3-way: the difference
| Aspect | 2-way matching | 3-way matching |
|---|---|---|
| Compares | Invoice + PO | Invoice + PO + GR |
| Suitable for | Services, software, rent | Goods, materials, stock |
| Prevents duplicate payment | Limited | Fully |
| Detects partial deliveries | No | Yes |
| Setup complexity | Low | Medium |
When do you need 3-way matching?
It becomes worth it when you tick at least two of these:
- You process 100+ goods invoices per month.
- You work with purchase orders and goods receipts in Exact Online or another ERP.
- You have partial deliveries, price differences, freight charges, or surcharges on invoices.
- You've had duplicate or overpayments before.
- Your purchase volume is large enough that errors cost thousands per year.
How Glimps does 3-way matching in Exact Online
Glimps' matching engine works in three automated steps: extract invoice data at line level, compare with open PO lines and goods receipts via direct Exact Online integration, then apply tolerances and route exceptions.
Conclusion
3-way matching isn't a luxury for enterprise. For any company with serious goods volume it pays back within months — sometimes weeks. The key is line-accurate extraction combined with smart tolerances and well-routed exceptions.
Glimps offers native 3-way PO matching for Exact Online. Learn more about the matching engine or try it in our demo.