What is accounts receivable? Definition, examples, and process

Accounts receivable (AR) is the money customers owe a business for goods or services delivered on credit but not yet paid for. It appears as a current asset on the balance sheet and represents cash the company has earned and expects to collect, usually within 30 to 90 days.

It helps to think of accounts receivable not as a static balance sheet line but as a process that runs from the moment an invoice goes out to the moment cash lands and gets applied. That process, invoicing, reminding, collecting, applying cash, and resolving disputes, is where the value either gets collected on time or quietly leaks away. Increasingly, that whole process can run itself.

What is accounts receivable

When a business sells on credit, it delivers the product or service first and gets paid later. The unpaid amount is the receivable. For example, if a supplier ships 50,000 of goods on net-30 terms, it records 50,000 in accounts receivable and waits up to 30 days for the cash.

Receivables exist because credit terms are how most B2B commerce works. Customers expect to pay after delivery, not before. That convenience comes with a cost: the seller is effectively lending money to its customers, and the longer the receivable stays unpaid, the longer that cash is tied up.

AR on the balance sheet

Accounts receivable sits under current assets, because the company expects to convert it to cash within a year. It is recorded net of an allowance for doubtful accounts, the estimated portion the company does not expect to collect.

When an invoice is issued, AR is debited and revenue is credited. When the customer pays, cash is debited and AR is credited, clearing the receivable. The gross receivable balance is only worth what the company can actually collect, which is why the allowance matters: a large receivable balance full of aged, uncollectible invoices is worth far less than its face value.

The accounts receivable process

The AR cycle runs through five core steps:

1. Set credit terms. Decide who gets credit, how much, and on what terms (net 30, net 60, and so on) before the sale.
2. Invoice the customer. Generate and deliver an accurate invoice through the customer's preferred channel, including portals that require manual upload.
3. Follow up and collect. Send reminders on a cadence, escalating as the invoice ages, and chase overdue accounts.
4. Apply the cash. Match incoming payments to the right open invoices, including partial payments and remittances that arrive separately.
5. Resolve disputes and deductions. Handle short pays, chargebacks, and disputes, and route them to resolution so the receivable clears.

Each step that stalls, an invoice sent late, a reminder never sent, a payment misapplied, adds days to collection and trapped cash to the balance sheet.

AR vs accounts payable

Accounts receivable and accounts payable are mirror images of the same transaction.

• Accounts receivable is money owed to your business by customers. It is an asset.
• Accounts payable is money your business owes to suppliers. It is a liability.

One company's receivable is its customer's payable. Together they shape working capital: collecting receivables faster and managing payables sensibly frees up cash. The asymmetry most teams miss is that AR is the side they under-automate, even though slow collections trap cash directly.

Key AR metrics

A handful of numbers tell you whether the receivables function is healthy:

• Days sales outstanding (DSO): average days to collect after a sale. The headline AR metric.
• Collection effectiveness index (CEI): the percentage of collectible receivables you actually collected.
• Aging: the breakdown of receivables by how overdue they are, which flags risk early.
• Bad debt expense: the cost of receivables you no longer expect to collect.

Watched together, these show both how fast and how completely you collect, and where cash is getting stuck.

How automation changes AR

For most of its history, accounts receivable has been manual: people sending invoices, chasing payments, keying in cash, and researching disputes one at a time. That work is repetitive, follows patterns, and scales badly. As the volume grows, teams fall behind, invoices age, and cash leaks into write-offs.

Modern AR can run as a process that largely drives itself. The reminders go out on time, payments get matched automatically, disputes get routed, and the metrics stay current without anyone exporting a spreadsheet. The function shifts from typing and chasing to handling the exceptions that genuinely need a human.

How Rex runs accounts receivable end to end

Rex is an agentic AI accounts receivable agent. Rather than surfacing work for a person to do, it does the work: it follows up on aging invoices across the entire ledger, applies incoming cash to the right invoices, and resolves disputes and deductions, continuously and at scale. It treats AR as a process to run, not a report to read.

Rex handles the high-volume, rule-following work on its own and escalates only the cases that need a human decision, a strategic account to handle with care, a payment plan to approve, a genuinely ambiguous dispute. The team stops chasing invoices and starts working the exceptions. See how Rex runs collections end to end.