The Excel BETA.INV function is the inverse of the cumulative beta distribution: give it a probability and it returns the value of x at which that cumulative probability occurs.
Syntax
| Argument | Description | |
|---|---|---|
probability | Required | A probability between 0 and 1 associated with the beta distribution. |
alpha | Required | First shape parameter (α > 0). |
beta | Required | Second shape parameter (β > 0). |
A | Optional | Lower bound of x. Default 0. |
B | Optional | Upper bound of x. Default 1. |
How to use it
BETA.INV answers the reverse question to BETA.DIST: instead of "what is the probability at this x?", it asks "at what x does this cumulative probability occur?" It is the percentile finder for the beta distribution.
Because the two functions are inverses, =BETA.INV(BETA.DIST(x,…,TRUE,…),…) returns your original x. Use the same alpha, beta, A, and B in both.
Finding percentiles: pass 0.95 as the probability to find the 95th percentile of a beta-distributed variable — useful for confidence bounds on proportions.
Try it: interactive demo
Pick a BETA.INV example to see the formula and its result.
Practice workbook
Frequently asked questions
How does BETA.INV relate to BETA.DIST?
x into a cumulative probability; BETA.INV turns a probability back into the matching x — using the same shape and bound parameters.What must the probability argument be?
#NUM! error.Can I use BETA.INV to find a percentile?
0.9 for the 90th percentile — and BETA.INV returns the corresponding x.What replaced the old BETAINV?
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