The two documents look similar — both list items, prices, and a total — but they serve opposite purposes in a transaction. Get them confused and you can end up sending a client the wrong paperwork, or filing the wrong document for your own bookkeeping.

The one-sentence version

An invoice is a request for payment, sent before money changes hands. A receipt is proof of payment, issued after money changes hands. Everything else follows from that single distinction.

InvoiceReceipt
When it's issuedBefore paymentAfter payment
PurposeRequests money owedConfirms money received
Contains a due dateUsually yesNo — it's already paid
Legal weightA billing document, not proof of paymentProof of payment for accounting/tax purposes
Who needs itSeller (to get paid), buyer (to know what's owed)Buyer (for expense records), seller (for sales records)

Why the difference actually matters

Mixing these up creates real problems:

Simple test: If the money hasn't been paid yet, you need an invoice. If it has, you need a receipt. A single document almost never correctly serves both purposes.

What each document must include

An invoice typically needs: your business details, the client's details, a unique invoice number, itemized goods/services with quantities and prices, the total due, payment terms, and a due date.

A receipt typically needs: the same business and item details, but replaces the due date with the date payment was actually received, and often the payment method used (card, bank transfer, cash).

Do you ever need both?

Yes — this is the normal flow for most transactions: send an invoice when the work is complete and payment is due, then once the client pays, issue a receipt confirming that payment was received. Some businesses combine this into one document marked "PAID" after the fact, but keeping them separate gives cleaner records for both sides, especially for tax purposes.

Common mistake: Marking an invoice as "paid" by hand isn't the same as issuing a proper receipt. If your client needs the payment for their own expense records, send a dedicated receipt — some accounting systems and tax authorities won't accept a hand-annotated invoice as valid proof.