What is DSO (days sales outstanding)?
DSO is a single number that tells you how long, on average, your cash is stuck in customers' hands after a sale. The lower it is, the more of your own money you actually get to use.
Skip the math — the free accounts receivable aging tracker runs this from your own figures.
Open the free calculator →What DSO measures
Days sales outstanding is the average number of days it takes to collect payment after you've made a sale on credit. A DSO of 45 means, on average, your invoices sit unpaid for about 45 days before the cash arrives.
It's a direct read on how efficiently you turn sales into cash. Two businesses can book identical revenue, but the one with the lower DSO has far more cash on hand to pay staff, restock, and grow.
The formula
DSO = (accounts receivable ÷ total credit sales) × number of days in the period. For a full year: take your outstanding receivables, divide by annual credit sales, and multiply by 365.
Example: $60,000 in unpaid invoices on $500,000 of annual credit sales gives (60,000 ÷ 500,000) × 365 ≈ 44 days. That's your average time-to-cash.
What counts as a good DSO
There's no universal target — it depends on the payment terms you offer. A useful benchmark is to compare DSO to your standard terms: if you invoice net-30 but your DSO is 55, customers are effectively taking three extra weeks, and that gap is costing you cash.
As a rough guide, a DSO within about a third of your terms (so under ~40 for net-30) is healthy. A DSO climbing over time is a warning sign long before it shows up as a cash crunch.
How to lower your DSO
Invoice immediately and accurately — every day an invoice is late going out is a day added to DSO. Make terms explicit, offer easy payment methods, and consider small early-payment incentives or deposits up front.
Then chase systematically: a polite reminder before the due date, and prompt follow-up after. Most late payment isn't refusal — it's drift, and a consistent follow-up rhythm fixes most of it.
Watch aging, not just the average
DSO is an average, so it can hide a few badly overdue accounts behind lots of prompt payers. That's why DSO is best read alongside an accounts-receivable aging report that sorts every unpaid invoice into buckets — 0–30, 31–60, 61–90, and 90+ days overdue.
The free calculator below gives you your DSO and the cash tied up in receivables instantly, and the AR aging tracker breaks it down invoice by invoice so you know exactly who to chase first.
Questions
Is a lower DSO always better?
Almost always, because it means faster access to your own cash — but not at any cost. If you drive DSO down by demanding punishingly short terms or refusing credit to good customers, you can lose sales. The goal is the lowest DSO that doesn't cost you business: collect efficiently on sensible terms, rather than squeezing customers who would otherwise buy more.
What's the difference between DSO and an aging report?
DSO is a single average — how many days, on average, it takes to get paid. An aging report is the detailed breakdown behind it, grouping each unpaid invoice by how overdue it is. DSO tells you there's a problem; the aging report tells you exactly which invoices and customers are causing it.