Invoice Number
Definition
A unique identifier assigned to each invoice in a sequence, used to reference, track and reconcile it. Many tax systems require invoice numbering to be sequential and gap-free.
Related Terms in Invoicing & Sales
Debit Memo
A document that increases the amount a buyer owes a seller after the original invoice, for additional charges, undercharges or price corrections. It is the opposite of a credit memo.
Self-Billing
An arrangement where the customer, rather than the supplier, prepares the invoice on the supplier's behalf under an agreement. It is used where the buyer has better data on quantities or prices, such as commissions or royalties.
Accounts Receivable Aging
A report grouping unpaid customer invoices by how long they have been outstanding — current, 1–30 days, 31–60 days and so on. It shows where collection effort is needed and flags likely bad debts.
Accounts Payable Aging
A report grouping unpaid supplier bills by how long they have been outstanding, helping a business manage payment timing, avoid late fees and preserve supplier relationships while protecting cash.
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