MTBF & MTTR Calculator
Measure equipment reliability: enter operating hours, failures and downtime to get MTBF, MTTR and availability. Free, instant and fully in your browser.
Availability
98%
MTBF = uptime / failures · MTTR = downtime / failures
MTBF measures how long equipment runs between failures; MTTR measures how long repairs take. Availability = MTBF / (MTBF + MTTR). Raising MTBF and cutting MTTR both lift availability.
What are MTBF and MTTR?
MTBF (Mean Time Between Failures) and MTTR (Mean Time To Repair) are the two core reliability metrics for repairable equipment. MTBF captures how long an asset typically runs before it fails — higher is better. MTTR captures how long it takes to restore it — lower is better. Together they determine availability, the share of planned time the equipment is actually able to run, which feeds directly into OEE and capacity planning.
How to calculate MTBF and MTTR
- 1
Gather the log
From a maintenance period, record total operating (uptime) hours, the number of failures and total downtime hours.
- 2
Divide by failures
MTBF is operating hours divided by failures; MTTR is downtime hours divided by failures.
- 3
Read availability
Availability is MTBF divided by the sum of MTBF and MTTR — the share of time the asset can run.
Frequently asked questions
What is the difference between MTBF and MTTF?
MTBF is used for repairable equipment and measures time between failures. MTTF (Mean Time To Failure) is used for non-repairable items and measures time to the single failure. This calculator covers repairable assets, so it uses MTBF.
How do MTBF and MTTR relate to OEE?
Availability — derived from MTBF and MTTR — is the first of the three OEE factors. Frequent failures (low MTBF) or slow repairs (high MTTR) drag availability down and cap your OEE.
How does Yamazo Studio help?
Yamazo Studio analyses how work is actually done from video, including changeovers and stoppages, helping you standardise maintenance and changeover work to cut downtime — directly improving MTTR.
Related lean & quality tools
Cut downtime with standard work
Faster, standardised changeovers and repairs raise availability. Yamazo Studio turns shop-floor video into SMED and standard work — one offline Lean Operating Desk.
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