What Information Is on a Purchase Invoice

A purchase invoice is the bill a vendor sends you after fulfilling an order, and it needs ten pieces of information to be usable: vendor and buyer details, a unique invoice number, the purchase order (PO) number it's billing against, itemized goods or services with quantity and unit price, the tax amount, the total due, payment terms, a due date, and the vendor's payment details. Miss any one of those and you're either chasing the vendor for a fix or paying against a document you can't properly check. A purchase invoice is the vendor's half of a transaction your purchase order started, which is what separates it from an invoice you send out yourself.

What a Purchase Invoice Is

A purchase invoice is the document a vendor sends you once they've delivered the goods or completed the work you ordered. It's their formal request for payment, and it should reference the purchase order you sent them at the start of the transaction. If you've ever issued a PO through our purchase order generator and then waited for the vendor's bill to arrive, that bill is the purchase invoice.

It's easy to mix up with a purchase order because the two documents cover the same order from opposite ends. A purchase order is what you, the buyer, send to request goods at an agreed price. A purchase invoice is what the vendor sends back to bill you for delivering on that request. One asks, the other collects.

The Ten Fields a Purchase Invoice Needs

A usable purchase invoice includes all of the following. If a vendor's bill is missing more than one or two of these, send it back before you process payment rather than trying to fill in the gaps yourself.

1. Vendor details: the vendor's business name, address, and tax or VAT number.
2. Your business details: the buyer being billed.
3. A unique invoice number: the vendor's own reference for this specific bill.
4. The PO number it's billing against: the single most important field for matching this invoice back to what you ordered.
5. Itemized goods or services: each item, its quantity, and its unit price, laid out the same way your original PO did.
6. The tax amount and rate: shown separately from the subtotal, not folded into one number.
7. The total due: the full amount you're expected to pay.
8. Payment terms: how many days you have to pay, and by what method.
9. A due date: the actual date payment is expected, not just a term like "net 30".
10. Payment details: the bank account or payment method the vendor wants to be paid to.

Checking the Invoice Against the Original PO

Before you pay a purchase invoice, put it next to the PO you sent and check three things: the items match, the quantities match, and the unit price matches. Any difference is worth a question to the vendor before the payment goes out, not after.

When the Invoice Doesn't Match the PO

A mismatch is common and rarely malicious: a price change the vendor forgot to flag, a partial delivery billed as a full one, or a simple typo in the quantity. Send it back to the vendor and ask for a corrected invoice rather than paying the difference and sorting it out later. If they've already delivered against the wrong figure, the fix is a credit note against the original invoice, not a second invoice layered on top of the first.

Keeping a Clean Record

File every purchase invoice against the PO it belongs to, whether that's a folder, a spreadsheet, or the record inside whatever tool you used to send the PO in the first place. When a bookkeeper or accountant asks why a payment went out, "here's the PO we sent, here's the invoice that matches it" answers the question in one look. Our free purchase order generator keeps a record of what you sent, which makes that side-by-side check quick even months after the order shipped.