Days Sales Outstanding Calculator
Days sales outstanding (DSO) quantifies how long it takes your business to collect cash from credit sales. It is a critical metric for cash flow management because uncollected receivables are essentially interest-free loans to your customers. By tracking DSO monthly, you can detect early signs of deteriorating collections, identify customers who are slow to pay, and measure the effectiveness of your accounts receivable team. This calculator computes DSO from your accounts receivable balance and sales revenue for a given period.
Days sales outstanding formula
DSO = (Accounts Receivable / Sales) * Days in Period
AR Turnover = Days in Period / DSO
Example: AR $85,000, Sales $1,000,000, 365-day period. DSO = ($85,000 / $1,000,000) * 365 = 31.03 days. AR Turnover = 365 / 31.03 = 11.76 times per year.
Reducing days sales outstanding
- Send invoices immediately upon delivery or completion of service, not days later.
- Automate payment reminders at 7, 14, and 30 days past due.
- Offer a small early-payment discount (such as 2% if paid within 10 days) to accelerate collections.
- Review credit terms for chronically late-paying customers and consider shortening their terms.
- Accept multiple payment methods, including ACH and credit cards, to reduce payment friction.
Frequently asked questions
What is days sales outstanding?
Days sales outstanding (DSO) measures the average number of days it takes a business to collect payment after a sale is recorded. A lower DSO indicates faster collections and better cash flow management.
How is DSO calculated?
DSO = (Accounts Receivable / Total Sales) * Number of Days in Period. For an annual figure, use 365 days. For a quarterly DSO, use 90 days and the quarterly sales figure.
What is a good DSO?
A good DSO depends on your credit terms. If you offer net 30 payment terms, a DSO of 30 to 45 days is typical. A DSO significantly exceeding your terms suggests collection problems that need addressing.
How does DSO differ from the AR turnover ratio?
DSO and the AR turnover ratio convey the same information in different forms. AR Turnover = 365 / DSO. Some analysts prefer the AR turnover ratio; others prefer DSO because it directly shows the average collection lag in days.
What increases DSO?
DSO rises when customers pay late, when credit terms are extended, when disputes or billing errors slow collections, or when new credit sales are extended to customers with weaker payment histories.
Official sources
- FASB ASC 310: Receivables.
- SBA: Manage Your Business Finances.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.