Maintenance & Reliability calculator
Observed Mission Reliability Calculator
Measure the observed success percentage for a completed mission cohort. Use missions with the same duration, operating conditions and success definition, then enter your target.
What this calculator does
- Measure the success percentage of completed missions under the same stated conditions.
Formula used
- Observed reliability = successful missions ÷ completed missions × 100
- Failed missions = completed missions − successful missions
- Target shortfall = target reliability − observed reliability
Inputs explained
- Successful Missions: Whole completed missions meeting the defined success criterion.
- Completed Missions: Whole missions fully observed through the same required duration.
- Reliability Target: Your acceptance goal for the observed mission success percentage.
How to use the result
- Best suited to mission completion Review, repeated Duty-Cycle qualification.
- The observed percentage is not a statistical confidence guarantee. Censored missions and mixed mission lengths require another analysis.
Current U.S. benchmarks
- U.S. manufacturing runs at 75.7% of capacity (Federal Reserve, Aug 2026). New factory orders are up 8.5% year over year (Census).
Common questions
- Can I enter weighted equivalent missions? No, this model uses actual whole mission outcomes. Weighted equivalents have a different sampling basis and can exaggerate the amount of evidence.
- What should I do with a mission still running? Exclude it from this completed cohort and keep a separate censored-data record. Do not count unfinished missions as successes.
- Does 100% observed success certify the target? No, it describes the completed sample. Demonstrating population reliability requires a confidence method and sufficient independent observations.
- Can I mix short and long missions? No, use one defined mission duration and comparable conditions. Different exposure lengths can have different success probabilities.
Last reviewed 2026-10-06.