MTTR Calculator — Mean Time To Repair

"Repair time" is the total elapsed time from breakdown to back-in-production, not just hands-on wrench time. It includes:

• Fault detection — the gap between when the fault occurred and when it was noticed
• Response — how long until a technician arrives at the machine
• Diagnosis — identifying the root cause
• Parts wait — time sitting idle for a spare that isn't in stock — frequently the largest single component of MTTR
• Repair — the actual hands-on work
• Testing and handover — confirming the repair holds

A packaging machine had five breakdowns in one month, totaling 30 hours 45 minutes of repair time:

MTTR = 30h 45m ÷ 5 breakdowns = 6 hours 9 minutes

That looks like a slow maintenance team. It isn't. One of the five breakdowns — a bearing failure — was diagnosed in 45 minutes, but the replacement bearing wasn't in stock and had to be sourced overnight, adding roughly 20 hours to that single repair. Actual hands-on repair work across all five breakdowns totaled 9–10 hours; the rest was a stocking decision, not a technician problem.

MTTR alone tells you something is slow. Decomposing it by phase tells you what to fix.

MTTR and MTBF together determine Availability — the share of planned production time a machine actually ran. A machine that recovers faster (lower MTTR) and breaks down less often (higher MTBF) has higher availability, which is one of the three factors in OEE.

Run your MTTR number through the Availability calculator or the OEE calculator next, or check MTBF — how often the machine breaks down in the first place.