Supply Chain & Procurement calculator
Days of Supply Calculator
Calculate days of supply from inventory, daily usage, and policy factor. On-hand divided by daily usage, then divided by safety multiplier, gives a protected days of supply.
What this calculator does
- Calculate days of supply from inventory, daily usage, and policy factor.
- Use it when days of supply in supply chain and procurement is being sized for a buffer or safety stock review.
- Turns inventory on hand, daily usage, safety factor into a protected days of supply for days of supply in supply chain and procurement.
Formula used
- Protected days = inventory on hand ÷ daily usage ÷ safety multiplier
Inputs explained
- Inventory on hand: undefined
- Daily usage: undefined
- Safety factor: undefined
How to use the result
- Use it when days of supply in supply chain and procurement is being reviewed for stockout risk.
- Lead time variability and supplier reliability are not in the formula. Adjust safety multiplier to compensate.
Common questions
- How does this days of supply calculator help my supply chain and procurement team? Calculate days of supply from inventory, daily usage, and policy factor. You get a protected days of supply you can defend before quoting, scheduling, or sign-off.
- Where do I get the inputs for this supply chain and procurement calculator? inventory on hand, daily usage, safety factor usually move the protected days of supply most. Pull from measured supply chain and procurement runs, supplier data, and recent quotes rather than memory.
- What do I do with this number? Use protected days to set the next reorder point or buffer level for supply chain and procurement.
- What should I double-check before acting? Confirm daily usage is a real recent average, not a quarterly mean that hides a spike.
Last reviewed 2026-05-12.