Free tool
MTBF calculator
Mean Time Between Failures — how long a machine typically runs between breakdowns. Higher is better.
MTBF is a reliability metric — higher is better. It pairs directly with MTTR to give you availability: MTBF ÷ (MTBF + MTTR).
How the calculation works
MTBF= total operating (uptime) time ÷ number of failures over that time. It’s the average stretch of running time between one breakdown and the next — a reliability metric, not a speed or quality one. Higher MTBF means fewer, less frequent failures.
MTBF on its own only tells half the reliability story: it says nothing about how long each failure takes to fix. Pair it with MTTR (Mean Time To Repair) and you get availability: MTBF ÷ (MTBF + MTTR) — the standard reliability-engineering definition, distinct from but related to OEE’s Availability component.
A rising MTBF over time is one of the clearest signals that maintenance investment is working; a falling one is an early warning worth acting on before it shows up as lost production.
This calculator is for one machine over one period, entered by hand. ThingConnect logs every stop and its duration automatically from controller data, so MTBF (and MTTR) update continuously instead of waiting for someone to tally failures at the end of the month.