What is days payable outstanding (DPO)?
Days payable outstanding measures how many days, on average, your business takes to pay its suppliers after buying on credit. The formula is accounts payable / average daily purchases. This calculator divides annual purchases by 365 to get average daily purchases, then divides the payables balance by that figure.
Use trade payables plus notes payable for the balance. Averaging the beginning and ending balances gives a steadier number for seasonal businesses. Annual purchases are the textbook denominator, but if you do not track purchases separately, annual cost of goods sold works as a close substitute for trend analysis.
A longer DPO means you hold on to cash longer, which helps working capital. Stretched too far past the agreed terms, though, it turns into late payment, which can cost you supplier credit or early-payment discounts. Read DPO alongside DSO (days sales outstanding) and DIO (days inventory on hand) to get the cash conversion cycle - and keep all three on the same 365-day basis so they stay comparable.
Written as of September 2026. This calculator is for reference only and is not an accounting or tax filing document. Confirm closing figures and financing decisions with your accountant or CPA.
Frequently asked questions
Yes, for trend analysis. Small businesses that do not track purchases separately can use cost of goods sold. When inventory swings sharply in a period, purchases and COGS diverge, so use actual purchases when you have them.
For cash flow, longer is easier. But anything past the agreed terms is a late payment, and early-payment discounts you skip have a real cost. Compare the result with your contract credit days to see whether you are still inside the terms.