Both documents ride along with an order, and it's an easy mistake for a new e-commerce seller to think one covers the other. They're built for different audiences asking different questions.
| Packing Slip | Invoice |
|---|---|
| Confirms what's physically in the box | Requests or confirms payment |
| No pricing shown | Shows unit prices and totals |
| Travels inside the shipment | Often emailed separately, to accounts |
| Read by whoever receives the package | Read by whoever pays the bill |
Why prices don't belong on a packing slip
A packing slip is meant to be checked by whoever opens the box — a warehouse receiver, a gift recipient, an office assistant — who often shouldn't see pricing details meant for the buyer or accounts department. Leaving prices off is a deliberate, long-standing convention, not an oversight.
Why an invoice alone doesn't replace a packing slip
An invoice confirms what's owed, not necessarily what's physically enclosed in a specific box — especially for orders split across multiple shipments. A packing slip lets the recipient verify contents against what was actually ordered, independent of billing.
Businesses often send both, for different jobs
The invoice goes to whoever handles payment, often by email. The packing slip goes inside the physical shipment. Together they cover both the financial and physical sides of a transaction cleanly.