Inventory Days Coverage Calculator
How many days would usable stock cover at an entered average daily demand? Check the formula, a worked example and the stated measurement limits.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Usable stock (units) | Enter usable stock in units. Use the measurement basis described below. |
| Average daily demand (units/day) | Enter average daily demand in units/day. Use the measurement basis described below. |
Understanding your result
Use coverage to compare replenishment lead time with current stock exposure. Review seasonality and upcoming commitments instead of relying only on an historical average.
Common mistakes
- Include committed orders in the stock basis consistently.
- A recent demand spike may make a long-run average misleading.
- Mixing annual and monthly periods, or leaving out a cost that the model does not include.
Check your calculation
- Compare a simple one-period or zero-change case with hand arithmetic before applying a longer scenario.
Choose a consistent measurement basis
Use usable rather than damaged, reserved or unavailable stock. Match daily demand to the same SKU, location and demand period; distinguish business and calendar days.
A second independently worked case
No usable stock gives zero days of coverage. Inputs: Usable stock: 0 units; Average daily demand: 12 units/day. Results: Modeled days of stock: 0 days.
Precision and output units
Displayed results: Modeled days of stock in days, rounded to 3 decimal places. Display rounding does not establish the precision of the original measurements or estimates.
Calculation checks, sources and review limits
How many days would usable stock cover at an entered average daily demand?
How many days would usable stock cover at an entered average daily demand? Check the formula, a worked example and the stated measurement limits.
Common uses
- How many days would usable stock cover at an entered average daily demand
- Compare Inventory Days Coverage across scenarios under matching definitions.
How it works
Divide usable stock by positive average demand per day. The result is a rate-based scenario, not a prediction of the next actual stockout date.
Worked example
240 ÷ 12 = twenty days of coverage under constant daily demand. Enter usable stock 240 units, average daily demand 12 units/day. The independently worked result is modeled days of stock 20 days. Compare this example with your reporting definitions before substituting your own figures.
FAQ
Why does zero daily demand have no finite depletion estimate?
Without consumption, the constant-demand depletion equation has no finite duration. A future demand change or other stock movement requires a different scenario.
Are incoming deliveries included?
No. This divides the entered usable-stock snapshot by a demand rate. For dated replenishment and commitments, use a stock movement schedule rather than only an average rate.