Binomial Sample Size Calculator
Calculate the minimum sample size required to demonstrate a target reliability at a given
confidence level for pass/fail (attribute) testing. Supports zero-failure and
allow-failure test plans.
e.g. 90 for R90
e.g. 95 for C95
0 = success-run test plan
Demonstrated Reliability from Test Results
Given observed test results, compute the one-sided lower confidence bound on reliability
using the exact Clopper–Pearson (exact binomial) method.
Confidence Interval for Pass Rate
Exact Clopper–Pearson confidence intervals for an observed proportion. Use one-sided
lower for reliability demonstration; two-sided for symmetric bounds around a pass rate.
Weibull Reliability Calculator
Compute reliability metrics for the two-parameter Weibull distribution with assumed
shape (β) and characteristic life (η). Outputs R(t), hazard rate, B10 life, and MTTF.
β<1 infant · β=1 random · β>1 wear-out
63.2% cumulative failure age
Same units as η
Arrhenius Accelerated Aging Calculator
Calculate the thermal acceleration factor and equivalent use-life for
accelerated life testing. Based on the Arrhenius model with Boltzmann's constant.
0.5–1.0 eV typical for polymers
Series System Reliability Calculator
Compute the overall reliability of a series system where every component must function.
Add components, enter their individual reliabilities, then calculate.
Cpk / Margin-to-Spec Calculator
Calculate process capability indices (Cp, Cpk, Cpu, Cpl) and the estimated
defect rate. Assumes a normally distributed process. Leave a spec limit blank for
one-sided analysis.
Leave blank if not applicable
Leave blank if not applicable