Quick Navigation
GAMMA Function
Summary
The Excel GAMMA function calculates the gamma function value for a given number, a key mathematical function used in statistics, probability theory, and advanced calculations. It extends the factorial function to real and complex numbers.
Syntax
GAMMA(number)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| number | Number |
Yes | A positive real number. Negative integers and zero return #NUM! error. |
Using the GAMMA Function
Use GAMMA for statistical analysis, probability calculations, and when you need the gamma function value directly. It's particularly useful in data science, engineering, and financial modeling where gamma distribution parameters are involved.
Common GAMMA Examples
Basic GAMMA Calculation
=GAMMA(2.5)Returns 1.329340388 - gamma value for 2.5 (equivalent to 1.5!)
Negative Non-Integer Example
=GAMMA(-3.75)Returns 0.2680381636 - valid for non-integer negatives
Error Cases
=GAMMA(0)Returns #NUM! error since zero is invalid
Integer Factorial Check
=GAMMA(5)Returns 24 (equivalent to 4!)
Frequently Asked Questions
Common Errors and Solutions
#NUM!
Cause: Number is zero or negative integer
Solution: Use positive real numbers only
#VALUE!
Cause: Number contains non-numeric characters
Solution: Ensure input is a valid number
Notes
- Γ(n+1) = n × Γ(n) - recursive relationship
- For positive integers, GAMMA(n) = (n-1)!
- Use with GAMMA.DIST for gamma distribution analysis
- Available since Excel 2010
Compatibility
Available in: Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Excel 365
Not available in: Excel 2007, Excel 2003, Earlier versions
Content last reviewed: December 11, 2025
Update frequency: As needed
Excel versions tested: Excel 2010+