How the DSO Calculator works
Days Sales Outstanding (DSO) measures the average number of days it takes a business to collect payment after making a credit sale. It is a core accounts-receivable metric: a low DSO means cash is coming in quickly, while a rising DSO can be an early sign that customers are paying slower or credit terms have loosened.
The formula
DSO uses accounts receivable, total credit sales, and the number of days in the period being measured:
DSO = (Accounts Receivable / Total Credit Sales) × Number of Days
Accounts receivable is the outstanding balance customers owe you, typically taken at the end of the period (or averaged with the beginning-of-period balance for a smoother figure). Total credit sales should include only sales made on credit — cash sales are excluded because they carry no receivable. The number of days is the length of the period you are measuring: 30 for a month, 90 for a quarter, or 365 for a full year.
Worked example
Take $250,000 in accounts receivable and $1,500,000 in credit sales over a 365-day year. DSO = (250,000 / 1,500,000) × 365 ≈ 60.8 days. That means, on average, it takes this business about 61 days to convert a credit sale into cash. Average daily credit sales are $1,500,000 / 365 ≈ $4,109.59, and receivables turnover — how many times receivables are collected during the period — is $1,500,000 / $250,000 = 6 times, which is consistent since 365 / 6 ≈ 60.8 days.
DSO and receivables turnover
Receivables turnover and DSO describe the same underlying collection speed from two angles. Turnover ratio = Credit Sales / Accounts Receivable, expressed as a count of collection cycles per period. DSO = Period Days / Turnover Ratio, expressed in days. A higher turnover ratio always corresponds to a lower DSO, and vice versa — pick whichever framing is easier to communicate to your audience.
What moves DSO
- Accounts receivable balance: a larger uncollected balance for the same sales volume raises DSO directly.
- Credit sales volume: higher credit sales relative to the receivables balance lowers DSO, all else equal.
- Payment terms and collections practice: looser credit terms, slow invoicing, or weak collections follow-up tend to push DSO above the stated payment terms (for example, well above 30 days on Net 30 terms).
Comparing to a benchmark
There is no single "good" DSO that applies to every business — it depends on your industry, typical payment terms, and customer mix. A useful benchmark is either your own historical average or a peer figure from a similar business. This calculator compares your computed DSO against a benchmark value you enter so you can see, in days, whether collections are running ahead of or behind that reference point.