Plain definition
Days payable outstanding (DPO) estimates the average time taken to pay suppliers: average trade payables ÷ credit purchases × days in the period. Cost of sales is only a labelled approximation when credit purchases are unavailable.
Illustrative example
Monetary examples use Saudi riyals (SAR). The same principles apply in other currencies.
A buyer has average trade payables of and credit purchases in a 90-day quarter, giving DPO of 15 days. It then stretches payment to 30 days to protect cash. Procurement finds a key supplier will remove its discount, so the apparent cash improvement carries a price and supply consequence.
Why it matters
DPO reveals payment timing, but a rising number can mean negotiated credit or overdue suppliers. The distinction changes the management response.
Practical consequence
Reconcile payables to supplier statements, separate disputed invoices, and compare DPO with agreed terms and ageing. Do not use the metric to justify silent late payment.
Try your own numbers
Measure cash tied up in receivables and inventory, less supplier credit, then test a target cycle.
Working-capital cycle