The Excel BETADIST function returns the cumulative beta probability distribution. It still works in every version, but Microsoft replaced it in Excel 2010 with BETA.DIST, which adds a switch for the cumulative-vs-density form.
Syntax
| Argument | Description | |
|---|---|---|
x | Required | The value between the bounds A and B at which to evaluate the distribution. |
alpha | Required | The first shape parameter of the distribution (must be > 0). |
beta | Required | The second shape parameter of the distribution (must be > 0). |
A | Optional | The lower bound of the interval for x. Defaults to 0. |
B | Optional | The upper bound of the interval for x. Defaults to 1. |
How to use it
BETADIST returns the cumulative probability that a beta-distributed variable is at most x. The optional A and B rescale the standard 0–1 beta interval to any range.
Note the legacy argument order — x, alpha, beta — and that BETADIST only returns the cumulative value. The modern BETA.DIST requires an explicit cumulative flag, letting you also request the probability density.
Use BETA.DIST instead: in Excel 2010 and later, =BETA.DIST(2,8,10,TRUE,1,3) gives the same result and can also return the density when the flag is FALSE. BETADIST is retained only for older workbooks.
Try it: interactive demo
Pick a BETADIST example to see the formula and its result.
Practice workbook
Frequently asked questions
What is the modern replacement for BETADIST?
BETA.DIST, introduced in Excel 2010. It takes a cumulative argument so it can return either the cumulative distribution or the probability density. =BETA.DIST(2,8,10,TRUE,1,3) equals =BETADIST(2,8,10,1,3).Does BETADIST return the density or the cumulative probability?
x. To get the probability density you must use the modern BETA.DIST with its cumulative flag set to FALSE.What do the A and B arguments do?
x. If omitted, BETADIST uses the standard interval 0 to 1.Is BETADIST safe to keep using?
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