MTTF
Calculate MTTF instantly with the exact formula and a worked example.
MTTF
Units on test
Test durationh
Number of failures
Mean time to failure of failed unitsh
MTTF
7,200h
Failure rate
138.89per 10⁶ h
Median life
4990.7h
B10 life (10% failed)
758.6h
More about: MTTF
What it calculates
The “MTTF” calculator computes MTTF in h from 4 parameters: units on test, test duration (h), number of failures, mean time to failure of failed units (h).
A handy everyday calculator for daily tasks.
Example calculation
With parameters Units on test = 20, Test duration = 2,000 h, Number of failures = 5, Mean time to failure of failed units = 1,200 h the result is 7,200 h (Exponential model (constant failure rate)).
How to use
- Enter units on test, test duration, number of failures and mean time to failure of failed units — each field above is adjustable with a slider.
- MTTF (h) is calculated automatically as you type.
- Check the worked example below to see the formula applied to real numbers.
- Copy the result or bookmark this calculator.
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FAQ
How is MTTF calculated?
The MTTF calculator computes MTTF (in h) from units on test, test duration, number of failures, mean time to failure of failed units. Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the MTTF calculator free?
Yes. It is completely free, needs no signup, runs entirely in your browser, and sends no data to any server.
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