Days Sales Outstanding (DSO) Calculator

What this calculator does

Days Sales Outstanding measures how long, on average, it takes to collect cash after you make a credit sale. This tool turns your accounts receivable and credit sales into a single number of days. It's built for owners who want to know whether slow-paying customers are quietly tying up the cash their business needs to operate.

How it works

DSO = (accounts receivable ÷ credit sales) × days in the period. It expresses your outstanding receivables as an average number of days' worth of sales.

Use the same period for AR and sales (a year, a quarter, a month) and match the 'days in period' to it. Lower DSO means you're collecting faster and cash is coming in sooner.

A worked example

With $50,000 in accounts receivable against $500,000 in annual credit sales:

If your payment terms are net-30, a 37-day DSO means customers are paying roughly a week late on average — a manageable but worth-watching gap.

How to read your result

Compare DSO to your stated payment terms. If you offer net-30 and your DSO is 35–40, collections are reasonably tight. A DSO running well above your terms means cash is stuck in unpaid invoices — money you've earned but can't use. Rising DSO over time is an early warning of collection problems or customers in trouble. Lowering it (clearer terms, faster invoicing, follow-up, deposits) directly improves cash flow without selling a single extra unit.

Common mistakes

• ·Including cash sales. DSO is about credit sales only; mixing in cash or card-on-delivery sales understates the true collection time.
• ·Looking at one month in a seasonal business. A single period can mislead; track the trend across periods.
• ·Treating a low DSO as always good. An extremely low DSO can mean overly strict terms that cost you sales — balance collection speed against competitiveness.

Frequently asked questions