Inventory Days Calculator
Inventory days estimates how long average inventory would cover cost of goods sold at the chosen period pace.
How to use this calculator
- Enter average inventory value, COGS for the same period and number of days in that period.
- Check the labels and units before using a result outside this page.
- Change one input at a time if you want to compare scenarios.
Formula and method
Inventory days = average inventory value ÷ period cost of goods sold × days in period
- Inventory days = average inventory value ÷ period cost of goods sold × days in period
- Inventory value and COGS must use compatible accounting methods and periods; a zero average inventory makes turnover undefined.
Worked examples
Worked example
Average inventory 20,000; period COGS 120,000 over 180 days.
Inventory days = 20,000/120,000 × 180 = 30 days.
Inventory days = 20,000/120,000 × 180 = 30 days.
Understanding the result
Inventory days estimates how long average inventory would cover cost of goods sold at the chosen period pace.
Inventory value and COGS must use compatible accounting methods and periods; a zero average inventory makes turnover undefined.
Important notes
Inventory value and COGS must use compatible accounting methods and periods; a zero average inventory makes turnover undefined.
Displayed outputs are rounded for readability; preserve full precision when continuing a calculation.
Frequently asked questions
What does this inventory days calculator show?
Inventory days estimates how long average inventory would cover cost of goods sold at the chosen period pace.
Which inputs should I check first?
Enter average inventory value, COGS for the same period and number of days in that period.
Can the result be used as a final professional specification?
Inventory value and COGS must use compatible accounting methods and periods; a zero average inventory makes turnover undefined.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.