Purchase orders for small businesses: when and how

Use a purchase order when you buy above an agreed spending limit, from a new supplier, or for goods tied to a specific customer job. The order states what you are buying, the quantity, the price and the delivery date, and you check the supplier's invoice against it before paying.

Purchase orders can sound like big-company paperwork. In a small business they solve a small-business problem: someone ordered something, the invoice arrives a month later, and nobody remembers whether the price, the quantity or the order itself was ever agreed. A purchase order, or PO, is the written answer.

The documents in a buying flow

Document	Who creates it	What it does
Purchase requisition	The person who needs something	Asks internally for permission to buy. Many small teams skip it.
Purchase order	The buyer	Tells the supplier what you want to buy, at what price and by when
Order confirmation	The supplier	Accepts the order, or proposes changes to it
Goods receipt	The buyer, on delivery	Records what actually arrived and in what state
Supplier invoice	The supplier	Asks for payment for what was delivered

The supplier side of this flow depends on good supplier data. The guide to managing supplier records with bank and tax details covers what each record should hold.

When a small business needs purchase orders

• More than one person buys. Once purchases no longer go through a single owner, a PO shows who committed the money.
• Purchases are large or unusual. Set a limit; anything above it needs a PO and an approval.
• You buy for a customer job. A PO tied to the job lets you compare the cost with what you quoted.
• You hold stock. Open orders tell you what is already on its way, so nobody reorders the same goods twice.
• Your customers send you POs. If larger customers expect their PO number on your invoices, you already know how much matching helps.

If one person buys everything with a card and checks every bill, purchase orders may add more work than they save. Start where the money or the risk is.

The purchase order process, step by step

1. Raise the order. Pick the supplier, add the items with quantities and agreed prices, and set the delivery date and address.
2. Approve it. Orders above your limit go to the person who owns the budget before they leave the building.
3. Send it and get confirmation. The supplier confirms the order or comes back with changes. A changed order is a new version, not a silent edit.
4. Receive the goods. Count what arrives against the order and note shortages or damage on the delivery note.
5. Match the invoice. Compare the supplier's invoice with the order and the goods receipt before approving it for payment.
6. Pay and close. Pay on the agreed terms and mark the order closed, or leave it open if a back order is still to come.

Once the invoice is matched, it becomes a supplier bill like any other. The guide to tracking supplier bills next to customer invoices picks up from there.

Three-way matching, in plain terms

Three-way matching compares three documents before you pay: what you ordered (the PO), what you received (the goods receipt) and what you are asked to pay (the invoice). If all three agree on items, quantities and prices, the bill can be paid. If they do not, someone looks before money leaves.

Two-way matching skips the goods receipt and compares the order with the invoice. It suits services, where there is nothing to count at the door. Either way, small tolerances help: decide in advance whether a rounding difference needs a person.

What to put on a purchase order

• A PO number from its own sequence, and the date.
• Your company details and the supplier's details.
• The delivery address and the requested delivery date.
• Each line: description, supplier item code if they use one, quantity, unit and agreed unit price.
• Tax treatment, payment terms and the currency.
• An instruction to quote the PO number on the invoice.
• Who approved it, kept on your copy.

If the goods go into stock, the order quantities and units should match the units you count in; the guide to inventory management for small businesses explains why units matter.

Keeping approvals light

Purchase	Suggested rule
Routine, below your everyday limit	PO optional; the buyer decides
Above the everyday limit	PO required; the budget owner approves
New supplier	PO required; check the supplier's details before the order goes out
Equipment or long contracts	PO required; a second approver signs off

Pick the limit that fits your business and write it down. A rule that lives in one person's memory stops working the day that person is away. When several matched bills fall due together, paying supplier bills in one batch saves another round of manual work.

Frequently asked questions

Is a purchase order legally binding?

In many jurisdictions, a purchase order that the supplier accepts can form a binding contract. Print your terms on the order or link to them, and check the rules where you and the supplier are based for large or unusual orders.

What is the difference between a purchase order and an invoice?

The buyer sends a purchase order to place an order. The supplier sends an invoice to ask for payment. The PO is generally not a tax document; the invoice is, and it should quote the PO number so both sides can match them.

What is a goods receipt?

It is the buyer's record of what was delivered, checked against the purchase order. It is the middle leg of three-way matching and the place to note shortages, damage or wrong items.

Do I need purchase order approval as a small business?

Not for every purchase. Many small businesses set one spending limit and require approval above it, plus a check for new suppliers. That keeps routine buying fast while large commitments get a second look.