Accounts receivable metrics and KPIs that matter

Finance leaders judge accounts receivable on a handful of metrics. Each one answers a different question about the same cycle: how fast cash arrives, how completely it is collected, and how much of the book is at risk. No single number tells the whole story, so the metrics are read together and, more importantly, read as trends.

Days sales outstanding (DSO)

DSO is the average number of days it takes to collect payment after a credit sale.

DSO = (Accounts Receivable / Total Credit Sales) x Number of Days

It is the headline AR metric because it converts the health of the whole collections process into one figure. A good DSO sits well inside your payment terms: on net-30, under 40 is healthy. DSO reacts to the size and timing of sales, so a spike in revenue can move it even when collections are fine. Watch the trend rather than the absolute number.

Collection effectiveness index (CEI)

CEI is the percentage of available receivables a team actually collected in a period.

CEI = ((Beginning AR + Credit Sales - Ending Total AR) / (Beginning AR + Credit Sales - Ending Current AR)) x 100

Unlike DSO, CEI strips out the effect of changing sales volume and measures pure collections performance. The numerator is what you collected, the denominator is what was collectible. A score above 80 percent is strong, and the best teams hold the high 80s and 90s. Because DSO can be flattered or distorted by sales swings, CEI is the better gauge of whether the collections function is working.

Average days delinquent (ADD)

ADD is the average number of days an invoice is paid past its due date.

ADD = DSO - Best Possible DSO

Best possible DSO is what DSO would be if every customer paid exactly on terms, calculated as current receivables divided by credit sales times the number of days. The gap between actual DSO and that floor is ADD. Where DSO measures total collection time, ADD isolates lateness, so it tells you how far behind your customers are running on average. A small and stable ADD means slippage is contained; a widening one means accounts are aging.

Aging buckets

The aging report sorts open receivables by how long they have been outstanding, usually into current, 1 to 30 days past due, 31 to 60, 61 to 90, and 90-plus. There is no formula, just a sum of balances in each band.

It is the most operational of the AR metrics because it tells you where to act. The percentage of the total book sitting in each bucket is what matters: a healthy ledger keeps the vast majority in current and the 90-plus band thin. When balances drift into the older buckets, the probability of collecting them falls sharply, which is why aging is the leading indicator behind a rising DSO. Track the share in each bucket over time, not just the dollar totals.

Bad debt ratio

The bad debt ratio is the share of credit sales a company writes off as uncollectible.

Bad Debt Ratio = (Bad Debt / Total Credit Sales) x 100

It is the lagging measure of collections risk, the receivables that aging and ADD warned about and that were never recovered. A low ratio, typically well under 1 percent for most businesses, signals sound credit policy and disciplined follow-up. A rising ratio points back upstream, to credit decisions that were too loose or to accounts that were left to age past the point of recovery.

Reading them together

These metrics interlock. Aging buckets and ADD are the early warning, DSO is the running summary, CEI is the report card on the team, and the bad debt ratio is the final cost when collection fails. A finance team that reads all five sees both the symptom and the cause, which is the difference between reacting to a bad month and preventing one.

The hard part is keeping the numbers current. Metrics calculated from a stale export describe last quarter, not today. Agentic AR systems like Rex keep DSO, aging, and the rest live as cash applies and invoices age, so the trend is visible while there is still time to act on it.