The formula is straightforward: MTBF = (Total operating hours) ÷ (Number of failures). A commercial fryer that ran 3,000 hours last quarter with three unplanned failures has an MTBF of 1,000 hours.
MTBF only measures between failures — it ignores the time spent repairing. That's why it's almost always reported alongside MTTR (Mean Time To Repair). Together they describe both the frequency and severity of a breakdown pattern.
Track MTBF per asset class (fryers, walk-ins, ovens) rather than per individual unit. Per-unit numbers fluctuate too much in a single location to be useful.