What is DSO (days sales outstanding)?

Days sales outstanding, defined

DSO (days sales outstanding) is the average number of days between a sale and the collection of payment for it. It tells you how long your cash sits with customers as accounts receivable instead of in your bank.

Because it compresses your receivables into one trackable number of days, DSO is the metric finance teams use to judge whether collections is improving or slipping.

How to calculate DSO

The standard formula is DSO = (accounts receivable ÷ total credit sales) × number of days in the period. For a month, divide your ending AR balance by the month’s credit sales and multiply by about 30.

Example: $300,000 in receivables on $600,000 of monthly credit sales gives a DSO of (300,000 ÷ 600,000) × 30 = 15 days.

What is a good DSO?

A good DSO is generally within about 15 days of your stated payment terms — so on Net 30, a DSO under roughly 45 days is healthy. The right benchmark depends on your industry, terms, and customer mix, so watch the trend more than the absolute number.

For tactics, see our full guide on how to reduce DSO.

How to lower DSO

DSO drops when follow-up is consistent across every overdue account, paying is frictionless, and incoming payments are matched to invoices the day they land. Most DSO is lost to delay — unwritten reminders, unread replies, late reconciliation — not outright refusal to pay.

An autonomous collections agent attacks each of those delays at once, which is why automating follow-up and cash application is one of the most reliable ways to bring DSO down.

Frequently asked questions

Is a lower DSO always better?

Generally yes, but an extremely low DSO can signal overly strict credit terms that cost you sales. Aim for a DSO close to your payment terms with a stable or falling trend.

Related terms

Cash application · AR aging · Accounts receivable · Dunning · Browse the full glossary →