The formula
Days payable outstanding answers one question: how many days, on average, do you take to pay your suppliers. Divide accounts payable by the cost of goods sold, then multiply by the days in the period. A DPO of 30.00 days means suppliers wait a month, on average, to be paid.
Step 1 — Find the accounts payable
Start with the accounts payable: the money you still owe suppliers for goods or services already delivered, from the balance sheet. It is the unpaid supplier invoices at the end of the period. On the worked example the accounts payable is $150,000.00.
Step 2 — Find the cost of goods sold
Now find the cost of goods sold in the period, from the income statement. Only CREDIT purchases count — the cost of goods sold stands in for the purchases made on credit, because most businesses buy their stock on terms. Cash purchases are excluded, because cash is already paid. On the worked example the cost of goods sold is $1,825,000.00.
Step 3 — Divide the accounts payable by the cost of goods sold
Divide the accounts payable by the cost of goods sold: the share of the period’s costs still sitting unpaid. On the worked example it is $150,000.00 ÷ $1,825,000.00 = 0.082192.
Step 4 — Multiply by the days in the period
Multiply that share by the days in the period, usually 365 for a year or 90 for a quarter. On the worked example it is 0.082192 × 365 = 30.00 days.
Step 5 — Work out the accounts payable the target needs
Multiply the cost of goods sold by the target DPO and divide by the days in the period. For a 30-day target, the accounts payable needed is $1,825,000.00 × 30 ÷ 365 = $150,000.00. To reach a 40-day DPO on the same costs, the smallest whole-dollar accounts payable is $200,000 — at $199,999 the payables are $1 short of the $200,000 needed, and the unrounded DPO is 39.999800 days, which displays as 40.00 days after rounding.
Step 6 — Work out the cost of goods sold the target needs
Multiply the accounts payable by the days in the period and divide by the target DPO. For a 30-day target, the cost of goods sold needed is $150,000.00 × 365 ÷ 30 = $1,825,000.00. The smallest whole-dollar cost of goods sold for the DPO to stay at or below 25 days is $2,190,000 — at $2,189,999 the costs are $1 short of the $2,190,000 needed.
Step 7 — Check the result against the 30-day typical line and the 60-day slow line
Under 30 days means you pay suppliers fast, 30 to 45 days is typical for many businesses, and over 60 days usually means you are holding onto cash longer — good for your bank balance, hard on your suppliers. On the worked example the DPO is 30.00 days, so the business sits right on the typical line. The largest whole-dollar accounts payable for the DPO to stay at or below 15 days is $75,000, and to stay at or below 45 days it is $225,000.
Three worked examples
The headline example: $150,000.00 of accounts payable and $1,825,000.00 of cost of goods sold over 365 days. The DPO is $150,000.00 ÷ $1,825,000.00 × 365 = 30.00 days, the payables needed for the 30-day target are $150,000.00, and the costs needed are $1,825,000.00. With $75,000.00 of payables instead, the DPO is 15.00 days; with $912,500.00 of costs, 60.00 days; with $225,000.00 of payables, 45.00 days; over a 90-day period, 7.40 days; with $37,500.00 of payables, 7.50 days; with $3,650,000.00 of costs, 15.00 days; with $0.00 of payables, 0.00 days — nothing owed. Use the days payable outstanding calculator for your own numbers.
Two reverses to check your answer
The largest whole-dollar accounts payable for the DPO to stay at or below 30 days is $150,000 — at $150,000 the DPO is 30.00 days; at $150,001 the payables are $1 over the $150,000 allowed, with an unrounded DPO of 30.000200 days, which displays as 30.00 days after rounding. The smallest whole-dollar cost of goods sold for the DPO to stay at or below 25 days is $2,190,000 — at $2,190,000 the DPO is 25.00 days; at $2,189,999 the costs are $1 short of the $2,190,000 needed, with an unrounded DPO of 25.000011 days, which displays as 25.00 days after rounding.
What average accounts payable is, and why it is an average
Average accounts payable is (opening accounts payable + closing accounts payable) ÷ 2: the payables at the start plus the payables at the end, divided by two. A single end-of-period snapshot misleads: a business that buys heavily in December and pays in January would show huge payables in December and small ones in February, and neither snapshot is the year. The average is steadier, because payables swing through the year.
What a high DPO means — and what a low DPO means
A high DPO means more purchases on credit but slower cash out: the goods are bought and the business is still holding the cash, so cash stays in the bank longer. A low DPO means cash leaves fast, but it can also mean suppliers are paid promptly and offer better terms. Retail businesses often run near 20 days; manufacturers often run 40 to 50 days; construction and professional services can run 60 days or more. DPO is the mirror of days sales outstanding: DPO = 365 ÷ accounts payable turnover, and DSO tests how fast customers pay you while DPO tests how fast you pay suppliers.
What to do when the DPO is high
A DPO over 60 days means each dollar of purchases takes more than two months to leave the bank. Hold onto cash longer by negotiating longer payment terms, taking early-payment discounts only when they beat holding the cash, and paying on the due date rather than early. The accounts payable needed for a 30-day DPO is $150,000.00 — every dollar paid below that line pulls the DPO down.
How days payable outstanding differs from inventory turnover, gross profit margin and days sales outstanding
Inventory turnover divides cost of goods sold by average inventory: it tests how fast STOCK sells, not how fast you pay suppliers. Gross profit margin divides gross profit by revenue: it tests what share of each sales dollar remains after the direct cost of goods sold, not the speed of payment. Days sales outstanding is the mirror image: it tests how fast customers pay YOU, while DPO tests how fast you pay suppliers. The cash conversion cycle combines all three into the full time from paying for stock to collecting the cash. DPO is the payables test; inventory turnover is the stock test; gross profit margin is the profit test. See the inventory turnover calculator and the guide to calculating inventory turnover, and the gross profit margin calculator.