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Mean time to repair (MTTR) is the average of, downtimes of a particular machine, for a particular time period. In other words, it is the average of times required to recover from its failures, for a particular time period.
MTTR and MTBF are closely related. You may read our article on MTBF.
How to calculate MTTR
MTTR is calculated by following formula,
Total downtime is the sum of all downtime of the machine for a particular period and no of Failures is the total no of breakdowns of the machine for a particular time period.
Sample calculation
Following is the data for a machine and we are going to calculate MTTR for a month.
| Element | Time |
| Duration of shift | 480 minutes |
| Total break duration per shift | 2 nos 15 minute tea breaks and 30 minute lunch break |
| Total downtime for the month | 1356 minutes |
| No of shifts scheduled per day | 3 |
| No of working days per month | 25 |
| Total no of failures for a month | 8 |
MTTR = 1356 / 8
= 169.5 minutes
We are done with the calculations.
What information caw we extract from MTTR
MTTR points out how quickly can a machine can be recovered from its failure. Better to always have lower MTTR.
Also, we can also compare the MTTR of machine with previous periods and judge the improvement in reduction in downtime.
I hope you got some knowledge regarding MTTR.
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I recently had an interview with EY India and I was asked “what is MTTR and MTBF” Luckily I had read this blog few days ago thus I was able to answer that question quite easily.
Thanks to Melvin for this easy to understand Blog🙏