Inventory Turnover Calculator

See how many times you sold through your average inventory in a period, and how many days stock typically sits before it sells.

Your numbers

▾

Cost of goods sold for the period

From your profit and loss for the period you're measuring.

Beginning inventory (at cost)

Ending inventory (at cost)

Days in the period

365 for a year, about 90 for a quarter, about 30 for a month.

days

Your result · updates as you type

Inventory turnover

6×

Cost of goods sold was 6 times your average inventory value over 365 days. On average, stock sat for 61 days before it sold.

Average inventory value: $30,000
Days inventory outstanding: 61 days
Annualized turnover: 6×/yr

There's no single healthy number: fast-moving categories like basics, groceries and beauty usually turn over far more than bulky or slow-moving categories like furniture or fine jewelry. Track your own trend over time, and compare it against your cash tied up with the GMROI calculator.

Breakdown

Beginning + ending inventory, ÷ 2: $30,000
Cost of goods sold: $180,000
Turnover (COGS ÷ average inventory): 6×
Days inventory outstanding (period days ÷ turnover): 61 days

Turnover and days inventory outstanding

Inventory turnover = cost of goods sold ÷ average inventory, where average inventory = (beginning inventory + ending inventory) ÷ 2

Days inventory outstanding (DIO) = days in the period ÷ turnover

Example: the default numbers, one year

Cost of goods sold: $180,000
Average inventory: ($28,000 + $32,000) ÷ 2 = $30,000

Turnover = 180,000 ÷ 30,000 = 6×. DIO = 365 ÷ 6 ≈ 61 days: stock sat for about two months on average before it sold.

Reading the result

There's no single healthy number: fast-moving categories like basics, groceries and beauty naturally turn over far more than bulky or slow-moving categories like furniture or fine jewelry. What matters more is your own trend over time, and whether turnover is falling while sales are flat, which usually means stock is aging.

Turnover falling, sales steady: you're likely overbought or holding dead stock. Check sell-through by SKU.
Turnover very high: you may be running too lean and risking stockouts. Check it against your reorder points.
Use a quarter or month to catch shifts sooner than waiting for a full year.

What to check next

Turnover tells you speed, but not profitability. Pair it with the GMROI calculator to see the gross margin dollars each SKU returns per dollar of inventory, and the sell-through rate calculator to check a specific batch or season.

Questions people ask

What's a good inventory turnover ratio?

It depends heavily on category. Compare your own turnover over time and against similar products in your catalog rather than a single external benchmark.

Should I use beginning and ending inventory, or an average across the year?

A true average across the year (monthly or quarterly snapshots) is more accurate if inventory swings a lot seasonally. Beginning and ending inventory is a reasonable approximation for a shorter period.

What does a low DIO mean?

Stock is selling quickly. That's usually good for cash flow, but check it isn't so low that you're stocking out and losing sales.

Is high turnover always better?

Not necessarily. Very high turnover on a product with thin margins can still be less profitable than slower turnover on a high-margin one. Check GMROI alongside turnover.

Last reviewed 30 September 2026.