WEIBULL.DIST Function in Excel: Weibull Distribution for Failure Times

WEIBULL.DIST Function in Excel: Weibull Distribution for Failure Times 1
⏱ 1 min readUpdated 5 October 2026

StatisticsLevel: ExpertAvailable in: Excel 2010+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. WEIBULL.DIST in practice
  5. Where you will use it
  6. Worked example
  7. Mistakes people make
  8. Related functions

WEIBULL.DIST models time to failure: the chance a machine part fails within x hours.

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Syntax

=WEIBULL.DIST(x, alpha, beta, cumulative)
Argument What it means
x Time
alpha Shape (>1 = wear-out)
beta Scale (characteristic life)
cumulative TRUE = failed by x

Examples

Example 1

=ROUND(WEIBULL.DIST(A2,B2,C2,TRUE),4)

Result: 0.0856. See the worked example table below for more cases.

WEIBULL.DIST in practice

Where you will use it

  • Reliability of machine parts
  • Warranty claims planning
  • Maintenance schedules

Worked example

HoursShapeScaleFormulaResult
10001.55000=ROUND(WEIBULL.DIST(A2,B2,C2,TRUE),4)0.0856
50001.55000=ROUND(WEIBULL.DIST(A3,B3,C3,TRUE),4)0.6321
800036000=ROUND(WEIBULL.DIST(A4,B4,C4,TRUE),4)0.9066

Results calculated in Excel.

Mistakes people make

MistakeWhat to do instead
Shape below 1Means early failures (infant mortality)
Negative time#NUM!

EXPON.DIST · WEIBULL

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