OEE & Factory Performance calculator
Constraint Buffer Time Calculator
Estimate protected buffer time from buffer stock and constraint usage. On-hand divided by daily usage, then divided by safety multiplier, gives a protected days of supply.
What this calculator does
- Estimate protected buffer time from buffer stock and constraint usage.
- Use it when constraint buffer time in oee and factory performance 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 constraint buffer time in oee and factory performance.
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 constraint buffer time in oee and factory performance is being reviewed for stockout risk.
- Lead time variability and supplier reliability are not in the formula. Adjust safety multiplier to compensate.
Common questions
- Why use this constraint buffer time tool for oee and factory performance? Estimate protected buffer time from buffer stock and constraint usage. You get a protected days of supply you can defend before quoting, scheduling, or sign-off.
- Which assumptions drive the protected days of supply? inventory on hand, daily usage, safety factor usually move the protected days of supply most. Pull from measured oee and factory performance runs, supplier data, and recent quotes rather than memory.
- How should I use the result? Use protected days to set the next reorder point or buffer level for oee and factory performance.
- What can throw the result off? Confirm daily usage is a real recent average, not a quarterly mean that hides a spike.
Last reviewed 2026-05-12.