Free DSO Calculator (Days Sales Outstanding)

Free DSO calculator

Work out your days sales outstanding in seconds, see how much of it is caused by late payment, and how much cash you would release by hitting your target. Nothing you type leaves your browser.

By Sudipta Ghosh · 20+ years in accounts receivable and order-to-cash · Updated 8 October 2026

Accounts receivable at period end (₹) Credit sales in the period (₹) Days in the period Not-yet-due (current) AR (₹) optional Your target DSO (days) optional

Your DSO–days

Best possible DSO–days

Average days delinquent–days

Cash you could release at target DSO–

Enter receivables and credit sales to see your result. Nothing you type leaves your browser.

How the calculator works

DSO = (Accounts receivable ÷ Credit sales) × Days in period

Best possible DSO = (Current, not-yet-due receivables ÷ Credit sales) × Days. The DSO you would have if every customer paid exactly on the due date.
Average days delinquent (ADD) = DSO − Best possible DSO. The days caused by late payment, which better collections can remove.
Cash you could release = (DSO − Target DSO) ÷ Days × Credit sales. The receivables that would turn into cash if you reached your target.

Tips for an accurate DSO

Use credit sales only. Cash sales were never in receivables.
Use the same basis for both numbers: both including GST, or both excluding it.
For seasonal businesses, calculate on a quarter or a rolling three months, not a single month.
Track the trend every month. A single DSO number matters less than its direction.

Your DSO higher than you would like? Read 12 practical steps to reduce DSO, or upload your ageing to the ageing strategy tool for a prioritised collection plan.

Frequently asked questions

How do you calculate DSO?

Divide accounts receivable at the end of the period by credit sales for the period, then multiply by the number of days in the period. For example, ₹3 crore of receivables and ₹2 crore of monthly credit sales gives (3 ÷ 2) × 30 = 45 days.

What is the difference between DSO and best possible DSO?

DSO uses total receivables. Best possible DSO uses only receivables that are not yet due, so it shows the DSO your payment terms would give if everyone paid on time. The gap between them is average days delinquent.

Should I include GST in the DSO calculation?

Use the same basis for both numbers. Receivables usually include GST, so compare them with credit sales including GST for an accurate DSO.