Inventory Turnover Calculator

Calculate inventory turnover, days sales in inventory and an annualized turnover from cost of goods sold and beginning and ending (or average) inventory.

Interactive calculator · Method INVENTORY-TURNOVER-1.0 · Last reviewed: 2026-11-04

Calculate your scenario

Average inventory = (beginning + ending inventory) ÷ 2, or the average you enter.

Your inputs

Try an example

Cost of goods sold for the period ($)

Average inventory from

Beginning inventory at cost ($)

Ending inventory at cost ($)

Average inventory at cost (if entered) ($)

Days in the period (365 year, 91.25 quarter) (days)

Default worked example. Edit the inputs to calculate your scenario.

Default worked example

Inventory turnover 5 times

Days in inventory 73 days

Average inventory $100,000.00

Annualized turnover 5 times per year

Turnover = $500,000.00 ÷ $100,000.00 = 5; days = 365 ÷ 5 = 73.

How to use the calculator

Enter cost of goods sold for the period, then either beginning and ending inventory or your own average, and the number of days the period covers.

What the result means

$500,000 of cost of goods sold over an average $100,000 of inventory is 5 turns a year, so stock sits about 73 days on average.

Formula and units

Average inventory = (beginning + ending inventory) ÷ 2, or the average you enter. Inventory turnover = cost of goods sold ÷ average inventory. Days in inventory (days sales in inventory) = days in the period ÷ turnover. Annualized turnover = turnover × 365 ÷ days in the period.

Worked examples

$500,000 COGS on $90,000 to $110,000 inventory: Cost of goods sold for the period: 500000 $; Beginning inventory at cost: 90000 $; Ending inventory at cost: 110000 $; Average inventory at cost (if entered): 100000 $; Days in the period (365 year, 91.25 quarter): 365 days; Average inventory from: begend.
Example result: Inventory turnover: 5 times; Days in inventory: 73 days; Average inventory: $100,000.00; Annualized turnover: 5 times per year.

One quarter: $150,000 COGS on $60,000 average: Cost of goods sold for the period: 150000 $; Beginning inventory at cost: 90000 $; Ending inventory at cost: 110000 $; Average inventory at cost (if entered): 60000 $; Days in the period (365 year, 91.25 quarter): 91.25 days; Average inventory from: avg.
Example result: Inventory turnover: 2.5 times; Days in inventory: 36.5 days; Average inventory: $60,000.00; Annualized turnover: 10 times per year.

Limitations and common mistakes

Use cost of goods sold and inventory at cost for the same period and the same business unit; mixing sales at retail with inventory at cost overstates turnover. A two-point average can hide seasonal peaks; a monthly average is steadier. No industry benchmarks are built in, and annualizing assumes the period is representative.

Using revenue instead of cost of goods sold, or a quarter’s COGS with 365 days, which makes days in inventory four times too long.

Sources and assumptions

Method INVENTORY-TURNOVER-1.0; last formula review 2026-11-04. Sources and their supported claims. Calculation methodology.