Equipment Availability
Equipment availability is the percentage of required or scheduled time during which an asset is capable of performing its intended function.
What this term means in maintenance
Equipment availability is the percentage of required or scheduled time during which an asset is capable of performing its intended function.
Scheduled-time availability formula
Equipment availability = (Scheduled time - Downtime) ÷ Scheduled time × 100
Practical example
An asset is scheduled for 1,000 hours and is unavailable for 80 hours.
Availability = (1,000 - 80) ÷ 1,000 × 100 = 92%
What availability indicates
Availability shows how much of the required time the equipment was ready for use. It is influenced by:
- Failure frequency
- Repair duration
- Planned maintenance
- Waiting time
- Setup and release rules
- The definition of downtime
Different availability definitions
Organizations may use operational availability, inherent availability, achieved availability, or production availability. The selected definition should match the business question being answered.
Relationship to reliability
Reliability concerns how long equipment performs without failure. Availability also reflects how quickly equipment is restored and whether it is ready when required.
Common mistake
Do not change the denominator from scheduled time to calendar time without making the change clear. Availability is comparable only when the time basis and downtime rules remain consistent.
How this term differs
Equipment Availability is a general measure of whether equipment was available during a defined required or scheduled period. It is related to Equipment Uptime, OEE Availability, and Operational Availability, 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.
Equipment Downtime
Equipment downtime is the period when an asset is required or scheduled to operate but is unavailable or unable to perform its intended function.
Mean Time Between Failures
Mean Time Between Failures, or MTBF, is the average operating time between failures of a repairable asset during a defined period.
Overall Equipment Effectiveness
Overall Equipment Effectiveness, or OEE, measures how effectively planned production time is converted into good output by combining availability, performance, and quality.
Glossary FAQs
- What is the equipment availability formula?
For scheduled-time availability, subtract downtime from scheduled time, divide by scheduled time, and multiply by 100.
- Is availability the same as reliability?
No. Reliability concerns failure-free operation, while availability also reflects repair and restoration time.
- Should planned maintenance count as downtime?
That depends on the selected availability definition. The rule should be documented and applied consistently.