What is Inventory Turnover?

Inventory turnover is calculated by dividing cost of goods sold (COGS) by average inventory. Using COGS rather than revenue provides a more accurate measure because inventory is recorded at cost. The resulting number indicates how many complete inventory cycles occurred during the year.

The reciprocal metric, days inventory outstanding (DIO), converts turnover into days: 365 divided by inventory turnover. A turnover of 12x means inventory is held for roughly 30 days on average. Grocery stores might have turnover of 14-20x (18-26 days), while jewelry stores may have turnover of 1-2x (180-365 days).

High inventory turnover is generally positive but must be balanced against stockout risk. Just-in-time (JIT) inventory systems maximize turnover but leave companies vulnerable to supply chain disruptions, as demonstrated during the COVID-19 pandemic. Many companies now maintain higher safety stock levels.

Declining inventory turnover relative to peers is a red flag that can indicate obsolete products, poor demand forecasting, or channel stuffing (shipping excess product to distributors to inflate revenue). Investors should compare turnover trends alongside revenue growth — if revenue is growing but turnover is declining, the company may be building inventory faster than it can sell.