Quick guide
How to use this calculator
- Choose whether to enter average inventory directly, calculate it from beginning and ending balances, or average a list of representative inventory snapshots.
- Enter cost of goods sold for the same reporting period and choose the exact number of days covered. Use consistent currency and inventory-valuation definitions.
- Choose a 365-day or 366-day annualization basis, then review period turnover, annualized turnover, inventory days, and the calculation method used.
Calculation method
Period-aware inventory turnover
Direct entry uses the average inventory supplied. The beginning-and-ending method divides their sum by two. The snapshot method divides the exact sum of 2 to 120 entered inventory balances by the number of observations.
Period turnover equals cost of goods sold for the reporting period divided by average inventory. Annualized turnover multiplies period turnover by annualization-basis days and divides by reporting-period days.
Implied inventory days equals reporting-period days divided by period turnover. When cost of goods sold is zero, turnover is zero and there is no finite turnover interval under the entered period.
Worked example
Annual beginning-and-ending example
COGS of 1,200,000, beginning inventory of 100,000, ending inventory of 200,000, and a 365-day period give average inventory of 150,000, turnover of 8 times, and 45.625 implied inventory days.
Average inventory is entered directly, calculated as (beginning inventory + ending inventory) ÷ 2, or calculated from inventory snapshots. Period turnover = period COGS ÷ average inventory; annualized turnover = period turnover × annualization-basis days ÷ reporting-period days; implied inventory days = reporting-period days ÷ period turnover.
Supported inputs
Precision and limits
Average inventory options
Enter average inventory directly, use beginning and ending inventory, or provide 2 to 120 representative plain-decimal balances, one per line without grouping separators. Snapshot averaging is arithmetic; it is not time-weighted when observations are unevenly spaced.
Period matching
Cost of goods sold and every inventory amount must cover the same reporting period and use a consistent valuation basis. Reporting periods accept 1 to 3,660 whole days.
Annualization and seasonality
Annualized turnover extrapolates the selected period using 365 or 366 days. Short or seasonal periods may not represent a full year and the output is not a forecast.
Interpretation boundary
Higher turnover is not automatically better. Stockouts, purchasing constraints, product mix, write-downs, obsolete goods, acquisitions, and unusual opening or closing balances can change the meaning.
Precision and privacy
Fixed decimals accept up to 30 digits and 12 decimal places, with each monetary input capped at 1e12. Calculations stay in the browser and exact nonzero supported values are not replaced by zero.
Decision boundary
This calculator does not choose an inventory valuation method, benchmark performance, diagnose stock levels, or provide accounting, tax, purchasing, or investment advice.
Continue calculating