Cas d'usage

Compare a purchase order with an invoice

Dernière vérification 7 September 2026 · Cette page est fournie en anglais.

To compare a purchase order with an invoice, join the two by item code within the supplier and check three things per line: the code you ordered, the quantity you ordered, and the unit price you were quoted. Price Double Check does this from a forwarded email and replies with the lines that differ.

The purchase order is your own document, so this comparison answers a question the invoice and the price list cannot: did the supplier ship what you asked for. You forward the PO from your Sent folder, the order confirmation and the invoice from your Inbox, and the reply lists every line where the invoice departs from the order, with the price list in force as the third reference for the unit price. No system to key the order into, no receipt to book, no tolerance to configure.

What the purchase order leg catches

An invoice checked only against a price list tells you whether each billed price is the list price, not whether the line should be on the invoice at all. Compare a purchase order with an invoice and that question is answered too. In the chain we validated the service on, from a sports-nutrition manufacturer to a Baltic distributor, the PO leg produced findings the price-list leg could not see.

• A substituted code. The order said one item, the invoice carries another, and nobody wrote to say so. In the validation chain a 550 cc bottle at 2.07 was invoiced as an 800 ml bottle at 2.59 under a neighbouring code: 15.60 more on one line, and the description on the invoice still read like the item that was ordered.
• A short delivery. The order says 24, the invoice says 18. The price per unit is correct, the line total is correct for 18, and the price list will not complain. Only the order knows that six are missing.
• An over delivery. More units billed than ordered, often a case-size rounding the supplier applies without telling you. The extra is real money at the correct unit price.
• A line you never ordered. Stands, catalogues, samples, a carriage charge: shown as unmatched to the order, with the amount, for you to decide.
• A price that moved between order and invoice. The order was placed under one price list, the invoice arrived under the next one. Whether the supplier honours the price at the date of the order is a matter of your terms, so the reply shows the order price, the invoice price and the delta, and does not judge.

Every finding is one row: code, description, quantity, billed, expected, delta, in your favour or against you. The comparison is by code and never by description: in the validation set 335 of 442 lines had a description that did not match the price list wording, and a text match would have failed on most of them.

The order confirmation is the middle document

Between your purchase order and the supplier's invoice sits a document most buyers file and never read again: the order confirmation, also called an order acknowledgement or sales order confirmation. It is the supplier restating your order in their own codes, quantities and prices, before anything ships. A pro forma invoice plays the same role for prepaid and export orders.

This document matters for two reasons. First, it is the earliest point at which a substitution or a price change becomes visible, weeks before the invoice and before the goods are on a pallet. A confirmation that says 800 ml where you ordered 550 cc is a finding you can act on with one email; the same finding on the invoice is a credit note negotiation. Second, when the confirmation and the invoice agree but your order does not, the change was the supplier's decision; when the invoice departs from the confirmation, it happened in the warehouse or on the accounts desk. The three documents tell you where the difference was born.

So the sequence is: forward the purchase order, then the confirmation when it arrives, and the reply to the confirmation is already a comparison against the order. The invoice is then compared to both, and to the price list for the unit price. The same forward that gives you the invoice against the price list gives you the order against the invoice; there is nothing extra to set up.

What a two-way match costs in an ERP

Accounts-payable software calls this comparison a two-way match: the invoice against the purchase order. A three-way match adds the goods receipt, a four-way match adds inspection. Each system allows a difference up to a tolerance before it raises a match exception and blocks the invoice for payment. The figures below are from the vendors' own documentation, read on 7 September 2026.

Two things are true of every row above ours. The comparison only exists once the purchase order has been keyed into that system, and it never checks whether the PO price was right in the first place. A PO typed from an old price list matches the invoice perfectly and pays the old price. The price list is the reference none of them hold, and it is the reference we add to the two-way match. The trade-off is honest: an ERP match blocks payment and routes the exception to an approver; we report and you act. If you already run a purchase ledger with matching switched on, keep it and use us for the price-list leg.

On tolerance: vendors let you set one because a one-cent difference on every line would bury the AP team in exceptions. The only difference we absorb is the one the arithmetic itself creates, a list price held at four decimals and billed at two. Anything beyond that is reported with its amount and ranked by size. A tolerance hides small differences; ranking shows them last.

The purchase order lives in Sent

The reason most distributors, importers and shops have no purchase-order matching is not the licence. The PO they send the factory is a PDF or a spreadsheet attached to an email, and no system can compare a purchase order with an invoice until somebody types it in again. IOFM's benchmarking puts a large share of invoices arriving in AP with no system PO behind them; the PO sits in Sent.

We treat the purchase order as a document, the same way we treat the invoice and the price list. You open Sent, find the order you emailed the supplier, and forward it to your personal address. The service reads the codes, quantities and prices from the attachment, joins them to the same supplier's price list and, later, to the confirmation and the invoice. Nothing is re-typed. If the order was written in the supplier's own order form, the codes are already theirs; if it was written in yours, the confirmation carries their codes and the join is made through it.

The steps, once per supplier and then per order.

1. Forward the supplier's current price list once. It stays on file.
2. Forward each purchase order from Sent, at the moment you send it or in a batch later.
3. Forward the order confirmation or pro forma when it arrives. The reply compares it with the order.
4. Forward the invoice. The reply compares it with the order, the confirmation and the price list, and lists what it could not match, with amounts.

The reply always states what it read and passes an arithmetic gate first: the sum of the extracted lines must equal the printed total to the cent before a single line is compared. On the validation chain 11 of 11 invoices agreed with their printed total to the cent, which is the reason to trust a line-level finding rather than a parser's best guess.

What the order comparison does not do

• It does not check the goods against the delivery note or a goods receipt. The three-way leg, receipt against invoice, is a warehouse count and stays with you.
• It does not judge units of measure. An order form that counts boxes where the invoice counts units looks like a short delivery; the reply shows the difference rather than calling it a shortfall.
• It does not judge freight. A carriage line has no reference price anywhere; it is shown with its amount and its share of the goods value.
• It does not block payment or route approvals. No workflow, no login, no integration; the reply is an email and the decision is yours.

For a purchaser who wants the full picture of what the chain of documents can prove without a purchase ledger, three-way matching without an ERP covers the receipt leg and where it stops. For the case where the quote, not the order, is the document that disagrees, see invoice does not match the quote.

Forward one invoice and the price list to your address, then the purchase order from Sent, and the reply names what was substituted, what was short and what was billed at another price.