Calculate Inventory Days of Supply (DoS) | Days Inventory Outstanding

Days In Inventory Calculation

An online inventory period calculator measures the average number of days the company holds its inventory before selling it.

Initial Inventory

Final Inventory

Cost of goods sold (COGS)

Average Inventory = (Beginning Inventory + Ending Inventory) / 2

Days in Inventory = 365 x Average Inventory / Cost of goods sold

Example

Inventory at the end of 2017 is $1000 and at the end of 2018 is $1200

Average inventory for 2018 = ($1000 + $1200) / 2

= $2,200 / 2

= $1,100

COGS per day = $7,300 / 365 = $20.

= $1,100 / $20

= 55 days

Inventory stayed in the system for an average of 55 days.