Key takeaways
- A purchase order comes from the buyer before the purchase; an invoice comes from the seller asking for payment; a receipt confirms payment.
- An accepted PO generally works as a contract between buyer and vendor.
- Small businesses usually need POs only for larger, repeat or multi-person purchasing.
- Matching the PO, invoice and delivery before paying is called a three-way match.
What is a purchase order?
A purchase order is a business saying, in writing, “we want to buy this, at this price, delivered by this date.” It has a PO number that the vendor puts on its invoice, which ties every later document back to the original order. That number is what keeps a busy business from paying for things nobody ordered.
A typical PO includes the buyer and vendor names, PO number and date, each item as a line item with quantity and unit price, the total, the delivery address and date, and payment terms such as “net 30.”
Keep receipts for what you ordered in one place with the Manage Receipt app.
PO vs invoice vs receipt
| Purchase order | Invoice | Receipt | |
|---|---|---|---|
| Created by | Buyer | Seller | Seller |
| When | Before the purchase | After delivery, before payment | After payment |
| Purpose | Order and agree terms | Ask for payment | Confirm payment |
| Shows items and prices | Yes | Yes | Usually |
| Proves you paid | No | No | Yes |
| Supports a tax deduction alone | No | With proof of payment | Usually |
The PO is a plan, the invoice is a bill, and the receipt is proof. For your tax records, the receipt or the paid invoice is what counts. The PO is useful backup that shows the purchase was authorized and what was agreed.
When small businesses need purchase orders
A freelancer buying a new laptop doesn’t need a PO. The overhead isn’t worth it. POs start to pay off when:
- More than one person can buy on behalf of the business.
- You order from the same vendors repeatedly, on credit terms.
- Purchases are large enough that a wrong price or quantity really hurts.
- Deliveries arrive in parts, and you need to track what’s still outstanding.
- A client, government agency or larger customer requires PO numbers on your invoices.
Many small teams set a simple rule: anything over a set amount, such as $1,000, needs a PO approved by the owner. Smaller costs go on a card with a receipt.
The purchase order process
- RequestSomeone asks to buy something and gets approval.
- Issue the POSend the vendor a numbered PO with items, prices and terms.
- ReceiveCheck the delivery against the PO and note any shortfalls.
- Match the invoiceCompare the vendor’s invoice with the PO and the delivery.
- Pay and filePay on terms, then keep the PO, invoice and receipt together.
Steps three and four are where most errors are caught. Larger teams formalize them through accounts payable; for a small business, a shared folder with the three documents side by side works fine.
Keep the paperwork for each order together
Scan or forward the vendor’s invoice and payment receipt into Manage Receipt and note the PO number with them. The scanner reads the vendor, date, line items and total, so checking them against your purchase order takes a glance, and the matched documents stay together for your records.
Explore AI Receipt ScannerFrequently asked questions
Is a purchase order legally binding?
Generally, yes once the vendor accepts it. Acceptance can be a signed copy, a written confirmation or simply shipping the goods. At that point the PO usually works as a contract on the stated items, prices and terms. Until it’s accepted, it’s only an offer. For important orders, get legal advice on your terms.
What is the difference between a PO and an invoice?
A purchase order comes from the buyer before the purchase and says what they want to buy. An invoice comes from the seller after delivery and asks to be paid. The invoice should reference the PO number, so the buyer can check that what was billed matches what was ordered.
Does a small business need purchase orders?
Not always. Sole owners making occasional purchases can rely on receipts and invoices. POs become useful when several people buy for the business, purchases are large or recurring, or customers require PO numbers. A simple rule, such as POs for anything over $1,000, keeps it manageable.
Can I deduct an expense with only a purchase order?
No. A PO shows what you planned to buy, not that you bought and paid for it. For tax purposes, keep the invoice with proof of payment or a receipt. The PO is helpful supporting evidence that the purchase was authorized and for business use.