Key takeaways
- A purchase order is issued by the buyer to request goods or services. A sales order is created by the seller to record and fulfil the order.
- The sales order is internal. It may follow the purchase order, a quote or a phone order.
- Both should agree on items, quantity, price and delivery date.
- The invoice should match both.
Free PDF and Excel: Order alignment check: sales order against purchase order. Get it below
The difference
A purchase order is a buyer's document asking a seller to supply goods or services. A sales order is a seller's internal document that records an accepted customer order and drives fulfilment.
| Feature | Purchase order | Sales order |
|---|---|---|
| Issued by | Buyer | Seller |
| Sent to | Seller | Internal, sometimes confirmed to the buyer |
| Purpose | Authorise a purchase | Record and fulfil a sale |
| Starts | Buyer's procurement process | Seller's order-to-cash process |
| Next document | Goods receipt, then invoice match | Pick list, delivery note, invoice |
| Number series | Buyer's | Seller's |
A full account of the buyer's document is on the site's purchase order guide. The seller side is covered on sales order.
A buyer sends PO 7781 for 500 units at 12 each. The seller creates SO 55120 and enters PO 7781 as the customer reference. The seller's system picks and ships 500 units, and the delivery note and invoice both cite SO 55120 and PO 7781.
If the seller had keyed 12.50, the invoice would not match the PO. Entering the PO number on the sales order is what makes matching possible.
Common problems
- Sales order keyed with a different price or date.
- No PO number on the sales order or invoice.
- Order changes made on one side only.
- Partial deliveries that confuse the match.
- Sales order quotes the customer PO number.
- Changes are confirmed in writing by both sides.
- Order acknowledgement is sent and checked.
- Invoice cites both numbers.
Last checked: 19 October 2026. General practice.
Free PDF and Excel
Order alignment check: sales order against purchase order
A side-by-side check sheet that compares a purchase order with the seller's sales order before shipment.
- Side-by-side check
- Mismatch types
- Change log
- Excel alignment register
Frequently asked questions
What is the difference between a sales order and a purchase order?
A purchase order is issued by the buyer. A sales order is created by the seller to record and fulfil the order.
Does the buyer see the sales order?
Not usually. The buyer may see an order confirmation derived from it.
Which comes first?
The purchase order, normally. Sometimes the sales order is created from a quote or phone order first.
Do the numbers need to match?
No, each side has its own numbers, but each should reference the other.
Is an invoice matched to the sales order or the purchase order?
The buyer matches it to the purchase order. The seller generates it from the sales order.