MTTR Calculator — Mean Time To Repair

MTTR = total repair (downtime) time ÷ number of repairs over that time. It’s the average time a breakdown keeps a machine down, from stop to running again — a measure of how fast your team recovers, not how often problems happen. Lower MTTR is better.

MTTR is the other half of the reliability picture that MTBF doesn’t capture. Together: Availability = MTBF ÷ (MTBF + MTTR) — the standard reliability-engineering definition, distinct from but related to OEE’s Availability component.

MTTR is usually the faster metric to improve — spare-parts stocking, clearer fault codes, and a documented repair procedure typically move MTTR before they move MTBF, which depends more on root-cause elimination over a longer horizon.

This calculator is for one machine over one period, entered by hand. MachDatum CMMS records every breakdown work order from report to close, so MTTR (and MTBF) update per asset as work orders close, instead of waiting for someone to tally repairs at the end of the month.