Returns the inverse of the cumulative beta probability density function for a specified beta distribution. That is, if probability = BETADIST(x,...), then BETAINV(probability,...) = x. The beta distribution can be used in project planning to model probable completion times given an expected completion time and variability.

Sample Usage



The BETAINV function syntax has the following arguments:

  • Probability     Required. A probability associated with the beta distribution.

  • Alpha     Required. A parameter of the distribution.

  • Beta     Required. A parameter the distribution.

  • A     Optional. A lower bound to the interval of x.

  • B     Optional. An upper bound to the interval of x.


  • If any argument is nonnumeric, BETAINV returns the #VALUE! error value.

  • If alpha ≤ 0 or beta ≤ 0, BETAINV returns the #NUM! error value.

  • If probability ≤ 0 or probability > 1, BETAINV returns the #NUM! error value.

  • If you omit values for A and B, BETAINV uses the standard cumulative beta distribution, so that A = 0 and B = 1.

Given a value for probability, BETAINV seeks that value x such that BETADIST(x, alpha, beta, A, B) = probability. Thus, precision of BETAINV depends on precision of BETADIST.

In order to use the BETAINV formula, start with your edited Excellentable:


Then type in the BETAINV Formula in the area you would like to display the outcome:


By adding the values you would like to calculate the BETAINV formula for, Excellentable will generate the outcome:


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