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BETADIST Function
Summary
The BETADIST function calculates the cumulative beta probability density, ideal for modeling proportions and percentages across sample data. This legacy function analyzes variation in fractional data like time allocation or success rates.
Syntax
BETADIST(x,alpha,beta,[A],[B])Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| x | Number |
Yes | Value between A and B to evaluate the distribution |
| alpha | Number |
Yes | First shape parameter (>0) defining distribution shape |
| beta | Number |
Yes | Second shape parameter (>0) defining distribution shape |
| A | Number |
No | Optional lower bound of interval (default: 0) |
| B | Number |
No | Optional upper bound of interval (default: 1) |
Using the BETADIST Function
BETADIST computes the cumulative distribution function (CDF) for the beta distribution, perfect for proportion analysis. Use it to model bounded probabilities between custom limits A and B, with shape controlled by alpha and beta parameters.
Common BETADIST Examples
Standard Beta Distribution
=BETADIST(0.5,8,10)Calculates cumulative probability at x=0.5 using standard bounds (0,1) with alpha=8, beta=10. Result: ~0.42
Custom Interval Example
=BETADIST(2,8,10,1,3)Evaluates distribution at x=2 within custom bounds A=1, B=3. Matches Microsoft example result: 0.6854706
Proportion Modeling
=BETADIST(A2,B2,C2,0,100)Models percentage distribution (0-100%) using cell values for parameters.
Frequently Asked Questions
Common Errors and Solutions
#VALUE!
Cause: Non-numeric input provided
Solution: Ensure all arguments contain valid numbers
#NUM!
Cause: alpha ≤ 0, beta ≤ 0, x < A, x > B, or A = B
Solution: Verify parameters meet distribution requirements
#NUM! with A=B
Cause: Lower and upper bounds are identical
Solution: Use distinct values for A and B
Notes
- Legacy function - Microsoft recommends BETA.DIST
- If A and B omitted, uses standard [0,1] interval
- Beta distribution frequently used for proportion modeling
- Returns cumulative probability value between 0 and 1
Compatibility
Available in: Excel for Microsoft 365, Excel for Microsoft 365 for Mac, Excel for the web, Excel 2024, Excel 2024 for Mac, Excel 2021, Excel 2021 for Mac, Excel 2019, Excel 2016
Not available in: Excel 2013 and earlier (use cautiously as deprecated)
Content last reviewed: December 8, 2025
Update frequency: As needed
Excel versions tested: Excel for Microsoft 365, Excel for Microsoft 365 for Mac, Excel for the web, Excel 2024, Excel 2024 for Mac, Excel 2021, Excel 2021 for Mac, Excel 2019, Excel 2016