Excel Weibull distribution is widely used in statistics to obtain a model for several data sets, the original formula to calculate weibull distribution is very complex but we have an inbuilt function in excel known as Weibull.Dist function which calculates Weibull distribution.
Syntax:= WEIBULL.DIST(x,alpha,beta,cumulative)
The WEIBULL.DIST function syntax has the following arguments:
 X Required. The value at which to evaluate the function.
 Alpha Required. A parameter to the distribution.
 Beta Required. A parameter to the distribution.

Cumulative Required. Determines the form of the function.
Example: Let’s look at some Excel WEIBULL.DIST function examples and explore how to use the WEIBULL.DIST function as a worksheet function in Microsoft Excel:
Suppose we are given the following data:
The formula to be used for the Weibull Cumulative Distribution Function is:
Syntax: =WEIBULL.DIST(B1,B2,B3,TRUE)
Result: 0.035020028
The formula to be used for the Weibull Probability Density Function is:
Syntax: =WEIBULL.DIST(B1,B2,B3,FALSE)
Result: 0.011768264
Note:
 If x, alpha, or beta is nonnumeric, WEIBULL.DIST returns the #VALUE! error value.
 If x < 0, WEIBULL.DIST returns the #NUM! error value.
 If alpha ≤ 0 or if beta ≤ 0, WEIBULL.DIST returns the #NUM! error value.

The equation for the Weibull cumulative distribution function is:
 The equation for the Weibull probability density function is:
 When alpha = 1, WEIBULL.DIST returns the exponential distribution with: