# The Excel F.INV.RT Function

Related Functions:
F.DIST.RT
F.INV

## Function Description

The Excel F.INV.RT function calculates the inverse of the (right-tailed) F Probability Distribution for a specified probability.

The function is new to Excel 2010 and so is not available in earlier versions of Excel. However the F.Inv.Rt function is simply an updated version of the Finv function, which is available in earlier versions of Excel.

The syntax of the F.Inv.Rt function is:

F.INV.RT( probability, deg_freedom1, deg_freedom2 )

Where the function arguments are:

 probability - The probability (between 0 and 1) at which to evaluate the inverse F Probability Distribution. deg_freedom1 - An integer specifying the numerator degrees of freedom. deg_freedom2 - An integer specifying the denominator degrees of freedom.

If either deg_freedom1 or deg_freedom2 are decimal numbers, these are truncated to integers by Excel.

Note that the Excel F.Inv.Rt function is the inverse of the Excel F.Dist.Rt function.

I.e. if
F.DIST.RT( x, deg_freedom1, deg_freedom2 ) = probability
then
F.INV.RT( probability, deg_freedom1, deg_freedom2 ) = x

## F.Inv.Rt Function Example

Inverse F Prob. Dist. with deg_freedom1 = 1 & deg_freedom2 = 2

The above chart on the right shows the inverse of the right-tailed F Probability Distribution with the numerator degrees of freedom equal to 1 and the denominator degrees of freedom equal to 2.

If you want to calculate the value of this function for a probability value of 0.2, this can be done using the Excel F.Inv.Rt function, as follows:

=F.INV.RT( 0.2, 1, 2 )

This gives the result 3.555555556.

For further details and examples of the Excel F.Inv.Rt function, see the Microsoft Office website.

## F.Inv.Rt Function Errors

If you get an error from the Excel F.Inv.Rt function this is likely to be one of the following:

Common Errors
 #NUM! - Occurs if either:The supplied probability is ≤ 0 or > 1orThe supplied deg_freedom1 or deg_freedom2 is < 1. #VALUE! - Occurs if any of the supplied arguments is non-numeric.