ShipCalculators.com

MTBF & MTTR

Mean Time Between Failures (MTBF) and Mean Time To Repair (MTTR) - two most-cited reliability metrics.

MaintenanceReliability
Loading calculator…

Formula, assumptions, and limits

MTBF=TopNfail,MTTR=TdownNfail\text{MTBF} = \frac{T_\text{op}}{N_\text{fail}}, \quad \text{MTTR} = \frac{T_\text{down}}{N_\text{fail}}
SymbolMeaningUnit
TopT_\text{op}Total operating hoursh
TdownT_\text{down}Total repair timeh
NfailN_\text{fail}Number of failures

Source: IEEE 493 - Reliability in Industrial Power Systems

In short

Mean Time Between Failures (MTBF) and Mean Time To Repair (MTTR) - two most-cited reliability metrics.

Learn the theory Cylinder Cover Design and Cooling: Two-Stroke Engines