Free tool
MTBF, MTTR & OEE Calculator
Calculate your equipment’s reliability (MTBF, MTTR) and Overall Equipment Effectiveness (OEE).
Period and downtime
Production and quality
Result: reliability and overall equipment effectiveness
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Request a maintenance strategy consultationHow the calculation works
The calculator computes: available time = period − planned downtime; actual run time = available time − failure time; MTBF = actual run time ÷ number of failures; MTTR = failure time ÷ number of failures; availability = actual run time ÷ available time; performance = produced ÷ (ideal rate × actual run time); quality = (produced − defects) ÷ produced; OEE = availability × performance × quality.
Example: a 720 h period, 40 h planned downtime, 8 failures totalling 24 h, an ideal rate of 100 units/h, 45,000 produced and 900 defects give MTBF 82.0 h, MTTR 3.0 h, availability 96.5%, performance 68.6%, quality 98.0% and OEE 64.9%.
Frequently asked questions
What is a good OEE?
85% and above is considered world class, 60% is a good level. In many factories actual OEE is lower.
What is the difference between MTBF and MTTR?
MTBF is the average time between failures, MTTR the average repair time per failure.
Where do I get the data?
From the machine log, a CMMS or production reports. If you have no data, use estimates and refine them later.
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Methodology and limitations
Methodology based on standard industry calculations and Maintest’s practical industrial experience. This tool provides a planning estimate and does not replace project-specific engineering assessment. This tool is a screening and planning aid developed by Maintest. Results are indicative and depend entirely on the figures and answers you enter. They are not an engineering calculation, a safety assessment or a substitute for the manufacturer’s instructions, applicable standards or professional judgement. Weights, benchmarks and default values are Maintest planning assumptions and can be adjusted to your situation. Do not use this tool as the only basis for safety-critical decisions such as lifting, electrical work or lockout procedures.
Tool version 1.0 · Updated October 2026
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