Weibull Analysis Calculator

Calculate reliability, hazard rate, and B-life from Weibull distribution parameters

Reliability R(t)Failure Rate

Weibull Analysis Calculator

β < 1: infant mortality | β = 1: random | β > 1: wear-out

Time at which 63.2% of units have failed

Guide to Weibull Distribution

What is Weibull Analysis?

The Weibull distribution is the most widely used distribution in reliability engineering. Unlike the simpler exponential distribution (constant failure rate), Weibull can model increasing, decreasing, or constant failure rates — making it suitable for real-world components.

R(t) = e^(-(t/η)^β)

Shape Parameter (β) Interpretation

β < 1: Infant mortality — failure rate decreases over time. Screen out early failures with burn-in testing.
β = 1: Random failures — constant failure rate. Reduces to exponential distribution.
β > 1: Wear-out — failure rate increases. Schedule preventive replacement before B10 life.
β ≈ 3.5: Approximates the normal distribution.

Typical β Values by Component

Componentβ RangeFailure Mode
Electronics (ICs)0.5 – 1.0Infant mortality → random
Bearings1.5 – 2.5Fatigue wear-out
Belts / Seals2.0 – 3.0Degradation wear-out
Gears2.0 – 5.0Tooth fatigue
Corrosion3.0 – 6.0Progressive degradation

FAQ

How do I get β and η from field data?

Plot failure times on Weibull probability paper (or use Maximum Likelihood Estimation). The slope gives β and the interception gives η. Minimum recommended data: 20+ failure times for reliable parameter estimates.

What is B10 life?

B10 life is the time at which 10% of units have failed (R = 90%). It is the most common reliability warranty specification. B1 life (1% failure) is used for safety-critical components.