Invoicing glossary
Invoice number
An invoice number is a unique identifier assigned to each invoice so it can be tracked, referenced, and reconciled.
Invoice number: a clear definition
Invoice numbers should be unique and sequential (e.g. INV-0001, INV-0002) so you and your clients can reference a specific invoice and so your records have no gaps. Most invoicing tools, including Invco, generate the next number for you automatically.
How Invco helps
Invco is an AI invoicing assistant that handles invoice number and the rest of your billing for you. Design a custom invoice template, then let Claude create and send invoices on it in plain English — with subtotals, tax, and totals calculated automatically and every invoice tracked from sent to paid. Start free with one company.
- Related terms: Purchase order, Tax invoice
Frequently asked questions
What is invoice number?
An invoice number is a unique identifier assigned to each invoice so it can be tracked, referenced, and reconciled.
What is purchase order?
A purchase order (PO) is a document a buyer sends to a seller to authorize a purchase, listing the items, quantities, and agreed prices.
Invoice the easy way with Invco
Let an AI assistant create and send your invoices on a template that looks like your brand. Start free with one company — no credit card required.
Get started — it's free