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BETA.DIST Function
Summary
The BETA.DIST function calculates the beta distribution, a flexible continuous probability distribution used to model variability in proportions and percentages across different samples. It's particularly valuable for quality control, project management, and Bayesian statistical analysis.
Syntax
BETA.DIST(x, alpha, beta, cumulative, [A], [B])Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| x | Number |
Yes | Value between A and B to evaluate the function |
| alpha | Number |
Yes | First shape parameter of the beta distribution (must be > 0) |
| beta | Number |
Yes | Second shape parameter of the beta distribution (must be > 0) |
| cumulative | Boolean |
Yes | TRUE for cumulative distribution function (CDF), FALSE for probability density function (PDF) |
| A | Number |
No | Optional lower bound of the interval (default: 0) |
| B | Number |
No | Optional upper bound of the interval (default: 1) |
Using the BETA.DIST Function
BETA.DIST is essential for statistical analysis involving proportions, success rates, or bounded continuous variables. Use cumulative=TRUE for CDF (probability that random variable ≤ x) or FALSE for PDF (probability density at x). Perfect for PERT analysis, quality control charts, and Bayesian inference.
Common BETA.DIST Examples
Cumulative Beta Distribution (CDF)
=BETA.DIST(2,8,10,TRUE(),1,3)Returns 0.6854706 - Probability that a beta-distributed variable ≤ 2 with α=8, β=10 over [1,3]
Probability Density Function (PDF)
=BETA.DIST(2,8,10,FALSE(),1,3)Returns 1.4837646 - Probability density at x=2 for the same distribution
Standard Beta Distribution [0,1]
=BETA.DIST(0.5,2,5,TRUE())Cumulative probability at 0.5 using standard bounds [0,1] with α=2, β=5
Frequently Asked Questions
Common Errors and Solutions
#VALUE!
Cause: Any argument is non-numeric
Solution: Ensure all inputs are valid numbers
#NUM!
Cause: alpha ≤ 0, beta ≤ 0, x < A, x > B, or A = B
Solution: Verify parameters are positive and x falls within bounds
#VALUE!
Cause: cumulative argument is not TRUE or FALSE
Solution: Use TRUE() or FALSE() for cumulative parameter
Notes
- If A and B are omitted, uses standard [0,1] interval
- Beta distribution parameters alpha and beta must be greater than 0
- x must always satisfy A ≤ x ≤ B
- Ideal for modeling proportions between 0 and 1
- Used in PERT project management for time estimates
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003 and earlier
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+