What does MTTR mean?

The MTTR (Mean Time to Repair or Mean Time to Recover) indicates the average time required to repair a failed system. It is also referred to as the mean repair time. The Mean Time to Repair indicates how quickly a company reacts to unplanned outages and how much time is required to repair the outages. A low MTTR means that the system can be repaired quickly, which reduces downtime.

How to calculate the MTTR?

MTTR is calculated by dividing the total unplanned maintenance time required for a plant or machine by the total number of failures of that plant, in a given period.

MTTR = Total unplanned maintenance time / Number of failures or repairs.


The total unplanned maintenance time of a machine has been 40 hours in 2022. In total, the plant has had 5 unplanned breakdowns.

40/5 = 8

The MTTR for this machine has been 8 hours in 2022.

What is the difference between MTTR, MTBF and MTTF?

  1. MTTR Mean Time to Repair refers to the average time required to repair and return a faulty plant or machine to service after a failure.

  2. MTBF Mean Time Between Failures refers to the average time that elapses between two consecutive failures.

  3. MTTF Mean Time to Failure refers to the average operating time before a plant or machine fails. Unlike MTBF, MTTF refers to the first occurrence of a failure rather than the average time between failures.

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