Days in inventory - Wikipedia
https://en.wikipedia.org/wiki/Days_in_inventoryDays in inventory (also known as "Inventory Days of Supply", "Days Inventory Outstanding" or the "Inventory Period" ) is an efficiency ratio that measures the average number of days the company holds its inventory before selling it. The ratio measures the number of days funds are tied up in inventory. Inventory levels (measured at cost) are divided by sales per day (also measured at cost rather than selling price.)