Stockout Rate
Stockout rate is the percentage of valid spare-parts requests that cannot be supplied from available stock when required.
What this term means in maintenance
Stockout rate is the percentage of valid spare-parts requests that cannot be supplied from available stock when required.
Formula
Stockout rate = Stockout demand events ÷ Total valid demand events × 100
Practical example
A store receives 400 valid item requests and cannot supply 20.
Stockout rate = 5%
Criticality view
Critical-spare stockouts should be reported separately because their consequence may be much higher.
Causes
Stockouts may result from poor reorder settings, inaccurate balances, supplier delay, unexpected demand, or obsolete parts.
Use with fill rate
Stockout rate and fill rate provide related but not always identical views depending on calculation basis.
Common mistake
Ignoring requests fulfilled through emergency purchase hides the original stockout.
How this term differs
Stockout Rate is the percentage of valid demand events affected by stockout. It is related to Inventory Fill Rate, Stockout, and Spare Parts Service Level, but these terms describe different records, measures, roles, strategies, or decisions and should not be used interchangeably.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
Stockout
A stockout occurs when a required spare part or maintenance material is unavailable when it is needed.
Spare Parts Service Level
Spare parts service level measures how reliably maintenance inventory can meet valid parts demand when required.
Inventory Fill Rate
Inventory fill rate is the percentage of requested spare-parts demand supplied immediately from available stock.
Glossary FAQs
- What is stockout rate?
The percentage of valid demand events that cannot be supplied when required.
- Should emergency purchases count as stockouts?
Yes. The original inability to supply should remain visible.
- Why report critical stockouts separately?
Their operational consequence is much higher.