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Inventory Days of Supply Calculator

Estimate how long available stock lasts at a specified daily demand.

Use a consistent reporting periodCheck the calculation below
Business dashboard
Business dashboard

Use figures from the same reporting period.

See the method

Enter your business figures

Runs on your device

Your key metric

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter available units, average daily demand.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Days of supply = available inventory / average daily demand.

A WORKED EXAMPLE

Using available units = 600 units, average daily demand = 20 units/day, the result is 30 days. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

Constant average demand and usable stock only. Supplier lead time, reserved stock and seasonal variation are not included.

What to keep in mind

Constant average demand and usable stock only. Supplier lead time, reserved stock and seasonal variation are not included. Use consistent currencies, reporting periods and accounting definitions. This arithmetic estimate excludes items not entered in the form.

Common questions

How do I use this inventory days of supply calculator?

Estimate how long available stock lasts at a specified daily demand. Enter available units in units, average daily demand in units/day. The starting example is editable; use values for the same system or project.

Which assumptions affect this result?

Constant average demand and usable stock only. Supplier lead time, reserved stock and seasonal variation are not included.

Methodology maintained by ClarityKit. How these tools are built and checked.