The Excel WEIBULL function returns the Weibull distribution, widely used in reliability and failure–time analysis. It is a legacy name — Microsoft now recommends WEIBULL.DIST, which is identical.
Syntax
| Argument | Description | |
|---|---|---|
x | Required | The value at which to evaluate the distribution (≥ 0). |
alpha | Required | The shape parameter (> 0). |
beta | Required | The scale parameter (> 0). |
cumulative | Required | TRUE returns the cumulative distribution; FALSE returns the probability density. |
How to use it
WEIBULL models time–to–failure and life–data. The alpha shape parameter controls how the failure rate changes over time; beta sets the scale.
Set cumulative to TRUE for the probability that a value falls at or below x, or FALSE for the density at exactly x.
Use the modern name: =WEIBULL.DIST(x, alpha, beta, cumulative) takes the same arguments and returns the same value. WEIBULL is kept only for backward compatibility.
Try it: interactive demo
Pick a WEIBULL example to see the formula and its result.
Practice workbook
Frequently asked questions
Is WEIBULL the same as WEIBULL.DIST?
WEIBULL.DIST (Excel 2010+) takes the same x, alpha, beta, and cumulative arguments and returns identical results. WEIBULL is kept for backward compatibility.What do alpha and beta control?
alpha is the shape parameter (how the failure rate changes over time) and beta is the scale parameter. Both must be greater than zero.What does the cumulative argument do?
Should I switch to WEIBULL.DIST?
.DIST family. Existing WEIBULL formulas keep working.Master functions like this in one day
This page covers one function. Our Excel Formulas and Functions class covers the 30 that matter most — live, hands-on, taught by professionals in Dallas–Fort Worth, Houston, Austin, Oklahoma City, Denver, or online.
See the Formulas & Functions Class