How to use GAMMA.INV Function in Excel

The GAMMA.INV function returns the inverse of the gamma cumulative distribution.

If p = GAMMA.DIST(x…), then GAMMA.INV (p…) = x. You can use this Function to study a variable whose distribution may be skewed.

Syntax:= GAMMAINV(probability,alpha,beta)

The GAMMA.INV function syntax has the following arguments:

  • Probability     Required. The probability associated with the gamma distribution.
  • Alpha     Required. A parameter to the distribution.
  • Beta     Required. A parameter to the distribution. If beta = 1, GAMMA.INV returns the standard gamma distribution.

Example: Let’s look at some Excel GAMMA.INV function examples and explore how to use the GAMMA.INV function as a worksheet function in Microsoft Excel:

Syntax:  =GAMMA.INV(B1,B2,B3)

Result: 3.037221607


  • If any argument is text, GAMMAINV returns the #VALUE! error value.
  • If probability < 0 or probability > 1, GAMMAINV returns the #NUM! error value.
  • If alpha ≤ 0 or if beta ≤ 0, GAMMAINV returns the #NUM! error value.

Given a value for probability, GAMMAINV seeks that value x such that GAMMADIST(x, alpha, beta, TRUE) = probability. Thus, precision of GAMMAINV depends on precision of GAMMADIST. GAMMAINV uses an iterative search technique. If the search has not converged after 100 iterations, the function returns the #N/A error value.


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