MTBF Calculator
Calculate observed MTBF and a constant-rate model probability, with zero-failure data left undefined.
A QUICK WALKTHROUGH
How to use this tool
- Enter the values below.
- Operating hours >0; failures are a nonnegative safe integer; interval ≥0. MTBF=hours/failures. Model probability=exp(−interval/MTBF), assuming a constant failure rate and comparable independent operating observations. MTBF is a sample statistic, not a service-life or reliability guarantee. Zero failures cannot establish a finite MTBF or a 100% probability; both outputs are undefined.
- Calculate and review the result.
Formula and scope
Operating hours >0; failures are a nonnegative safe integer; interval ≥0. MTBF=hours/failures. Model probability=exp(−interval/MTBF), assuming a constant failure rate and comparable independent operating observations. MTBF is a sample statistic, not a service-life or reliability guarantee. Zero failures cannot establish a finite MTBF or a 100% probability; both outputs are undefined.
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Inputs stay in this browser; nothing is sent.
GOOD TO KNOW
Common questions
How is it calculated?
Operating hours >0; failures are a nonnegative safe integer; interval ≥0. MTBF=hours/failures. Model probability=exp(−interval/MTBF), assuming a constant failure rate and comparable independent operating observations. MTBF is a sample statistic, not a service-life or reliability guarantee. Zero failures cannot establish a finite MTBF or a 100% probability; both outputs are undefined.