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GAMMA.DIST Function

Excel 2010+

Summary

The GAMMA.DIST function in Excel calculates the gamma distribution, ideal for modeling skewed data and time-to-event scenarios. Use it for queuing analysis, reliability engineering, and statistical modeling where traditional normal distributions don't fit.

Syntax

GAMMA.DIST(x, alpha, beta, cumulative)

Parameters

Parameter	Type	Required	Description
x	`Number`	Yes	Value at which to evaluate the gamma distribution (must be ≥ 0)
alpha	`Number`	Yes	Shape parameter of the gamma distribution (must be > 0)
beta	`Number`	Yes	Scale parameter of the gamma distribution (must be > 0)
cumulative	`Boolean`	Yes	TRUE for cumulative distribution function, FALSE for probability density function

Using the GAMMA.DIST Function

GAMMA.DIST is perfect for advanced statistical analysis in Excel. Set cumulative to FALSE for probability density at a specific point, or TRUE for the cumulative probability up to that point. When beta=1, it becomes the standard gamma distribution used in many statistical models.

Common GAMMA.DIST Examples

Probability Density Calculation

=GAMMA.DIST(10, 9, 2, FALSE)

Returns the probability density at x=10 with alpha=9, beta=2 (result: ~0.0326)

Cumulative Distribution

=GAMMA.DIST(10, 9, 2, TRUE)

Returns the cumulative probability up to x=10 with alpha=9, beta=2 (result: ~0.0681)

Exponential Distribution Case

=GAMMA.DIST(5, 1, 2, TRUE)

When alpha=1, returns exponential distribution cumulative probability

Frequently Asked Questions

GAMMA.DIST returns the exponential distribution, commonly used for modeling time between events.

When alpha=n/2, beta=2, and cumulative=TRUE, it equals 1-CHISQ.DIST.RT(x) for n degrees of freedom.

Yes, when alpha is a positive integer, it's known as the Erlang distribution.

Common Errors and Solutions

#NUM!

Cause: x < 0, alpha ≤ 0, or beta ≤ 0

Solution: Ensure x ≥ 0 and both alpha and beta > 0

#VALUE!

Cause: Non-numeric input for x, alpha, beta

Solution: Verify all numeric arguments are valid numbers

Notes

Available in Excel 2010 and later versions
Replaces the legacy GAMMA.DIST function
If beta=1, returns standard gamma distribution
Useful in operations research and quality control

Compatibility

Available in: Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365

Not available in: Excel 2007 and earlier

Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2010+