Inventory Turnover Calculator

Find inventory turnover and days of inventory from the cost of goods sold and the average inventory value. You can also work out the average from beginning and ending inventory.

Cost of goods sold (COGS) for the period

How to get the average inventory value

Beginning inventory value

Ending inventory value

Days in the period (the period of the cost of goods sold)

Rounding (turnover to 2 decimal places, days to 1 decimal place)

Inventory turnover —

Days of inventory —

Values used in the calculation
Cost of goods sold	—
Average inventory value	—
Days in the period	—

This is the common formula based on cost of goods sold (cost of goods sold ÷ average inventory). It is not a legal or regulatory definition. A version that uses sales as the numerator is not covered. An average of just two points (beginning and ending) does not reflect changes during the period, such as seasonal swings or large deliveries.

The values copied are the displayed numbers, without units or commas.

Formulas

Inventory turnover (times) = cost of goods sold ÷ average inventory value. How many times the inventory was replaced during the period.
Days of inventory (days) = days in the period ÷ inventory turnover, which equals average inventory × days ÷ cost of goods sold. The average number of days the stock is held.
Average inventory value = (beginning inventory + ending inventory) ÷ 2.

The tool calculates with exact fractions and rounds only once, when the value is displayed.

Amounts are entered in any currency you like. The tool does not use a currency symbol. Because turnover and days of inventory are ratios of two amounts in the same unit, the result does not depend on the currency. Amounts can have up to 2 decimal places, up to 9,999,999,999.99.

Days in the period

Days of inventory is calculated with the number of days in the period that the cost of goods sold covers.

A full year of cost of goods sold: 365 days (the default), or 366 days for a leap year.
A month or a quarter: choose 30, 31 or 90 days, or enter the number of days. Match the days to the period of the cost of goods sold. Using 365 days with one month of cost of goods sold makes the days of inventory far too large.

How zero values are handled

The tool separates "0" from "not available".

Cost of goods sold	Average inventory	Inventory turnover	Days of inventory
More than 0	More than 0	A normal value	A normal value
0	More than 0	0 times (nothing left the stock)	Not available (division by zero)
More than 0	0	Not available (division by zero)	0 days (see below)
0	0	Not available	Not available

The 0 days of inventory for an average inventory of 0 is a special case that follows from average inventory × days ÷ cost of goods sold = 0. It does not show that the stock was actually held for 0 days.

Examples

Cost of goods sold 12,000, beginning inventory 1,500, ending inventory 1,100 (average 1,300), 365 days: turnover about 9.23 times, days of inventory about 39.5 days.
Cost of goods sold 1,000 (one month), average inventory 1,300, 30 days (monthly): turnover about 0.77 times, days of inventory 39.0 days.
Cost of goods sold 0, average inventory 500: turnover 0 times, days of inventory not available.

Notes

A higher inventory turnover means the stock sells faster, but a good level differs by industry and product. This tool does not give a benchmark. Compare numbers for the same industry and the same method.
Value the inventory and the cost of goods sold on the same basis (for example, both at cost).
Amounts must be 0 or more, up to 9,999,999,999.99, with up to 2 decimal places. The average of the beginning and ending inventory can have a third decimal place (a half of the smallest unit); it is shown as it is.
To work with margins, see the Profit Margin Calculator. To count the days in a period, use the Date Difference Calculator. To find when to reorder, see the Reorder Point Calculator.

Frequently asked questions

What is a good inventory turnover?

It depends on the industry and the product, so this tool does not give a benchmark. Compare it with your own past values or with figures for the same industry that use the same method.

If inventory turnover is 12, how many days of inventory is that?

For a full year (365 days), 365 ÷ 12 is about 30.4 days.

Can I use sales instead of cost of goods sold?

Some explanations use sales, but inventory is usually valued at cost, so dividing cost of goods sold by average inventory compares like with like. This tool covers only the cost-of-goods-sold version.