MTTR calculator
Work out mean time to restoration for one asset from its failures and the hours each took to get back in service.
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Example only. The starting values are invented: the pump in the worked example below.
Mean time to restoration
The average hours from a breakdown until the asset is back in service.
Enter your own figures
- Failures restored. Enter 0 or more. The number of breakdowns repaired in the period. Do not count preventive or planned jobs.
- Restoration hours. Enter 0 or more. The hours from each breakdown until the asset was back in service, added together. Restoration hours are not labor hours: enter elapsed hours. Two technicians on one 3-hour job make 3 hours, not 6. Enter hours; 90 minutes is 1.5.
Enter one asset's figures. Pooling assets of different types gives a figure for none of them.
How the figure is worked out
MTTR (mean time to restoration) is the expected time from a failure, or from its detection when the failure moment is unknown, until the asset is back in service. The figure is the average over an asset’s breakdowns. A lower figure means assets get back into service sooner.
MTTR = R ÷ N
- R is restoration hours.
- N is the number of failures restored in the period.
R includes the hands-on work and the waiting for people, parts, approvals and access. Hands-on time alone is a different, smaller measure: mean repair time. It is not MTTR.
The MTBF and MTTR guide works through the method with a pump. Maintenance metrics and KPIs sets out when the restoration time starts.
A worked example, step by step
- Failures restored: 5
- Restoration hours: 40, the pump’s unplanned downtime, which included 14 hours of waiting for parts
MTTR = 40 ÷ 5 = 8 hours
Of those 40 hours, 26 were hands-on repair. Hands-on time alone is mean repair time: 26 ÷ 5 = 5.2 hours.