Days payable outstanding, or DPO, estimates the average number of days a business takes to pay trade suppliers. It relates accounts payable to credit purchases or, when that figure is unavailable, cost of goods sold. DPO is a period-level operating measure, not the contractual due date of a particular invoice.
How is days payable outstanding calculated?
A common formula is:
DPO = average accounts payable ÷ credit purchases × days in the period.
Average accounts payable is commonly calculated as beginning accounts payable plus ending accounts payable, divided by two. Some businesses substitute cost of goods sold for credit purchases because credit-purchase data is not separately available. That choice should be disclosed because it changes comparability.
Illustrative DPO calculation
| Calculation step | Arithmetic | Result |
|---|---|---|
| Average accounts payable | ($180,000 + $220,000) ÷ 2 | $200,000 |
| Credit purchases | Illustrative purchases during the quarter | $600,000 |
| Period length | Quarter used in the example | 90 days |
| DPO | $200,000 ÷ $600,000 × 90 | 30 days |
In this example, the business carried accounts payable equal to roughly 30 days of its credit purchases. The result does not mean every supplier was paid in 30 days; invoice timing and supplier terms can vary.
What can change DPO?
- Negotiated payment terms and early-payment discounts
- The mix of cash purchases and purchases on credit
- Seasonality and the timing of period-end purchases
- Invoice disputes, approval delays and payment holds
- Supplier concentration and changes in purchasing volume
How should DPO be interpreted?
A rising DPO can preserve cash for longer, but it may also indicate slower approvals, disputed invoices or supplier pressure. A falling DPO can reflect faster processing or deliberate use of discounts, but it can also consume working capital. Compare the measure across consistent periods and investigate the invoices and supplier terms behind the movement.
DPO vs. payment terms
Payment terms state when an individual obligation is due. DPO is an average produced from financial balances and period activity. A company can have Net 30 terms and a DPO above or below 30 days because of invoice timing, purchasing mix and exceptions.
