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EXPON.DIST Function
Summary
The EXPON.DIST function calculates the exponential distribution, ideal for modeling time between events in processes like service times or failure intervals. It provides both probability density and cumulative distribution values for statistical analysis.
Syntax
EXPON.DIST(x, lambda, cumulative)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| x | Number |
Yes | Value to evaluate (x ≥ 0) |
| lambda | Number |
Yes | Rate parameter (λ > 0) |
| cumulative | Boolean |
Yes | TRUE = CDF, FALSE = PDF |
Using the EXPON.DIST Function
EXPON.DIST is used in statistical modeling for exponential processes. Set cumulative to FALSE for the probability density at a specific point, or TRUE for the probability that the event occurs within that time. Perfect for analyzing service times, equipment failures, or inter-arrival times.
Common EXPON.DIST Examples
Cumulative Distribution Example
=EXPON.DIST(0.2,10,TRUE)Probability that event occurs within 0.2 units of time with rate 10 (returns ~0.8647)
Probability Density Example
=EXPON.DIST(0.2,10,FALSE)Density at exactly 0.2 units of time with rate 10 (returns ~1.3534)
Service Time Analysis
=EXPON.DIST(B2,$C$1,FALSE)PDF for customer service time analysis where B2 is time and C1 is average rate
Frequently Asked Questions
Common Errors and Solutions
#NUM! error
Cause: x < 0 or lambda ≤ 0
Solution: Ensure x ≥ 0 and lambda > 0
#VALUE! error
Cause: Non-numeric input for x or lambda
Solution: Verify inputs are valid numbers
Notes
- Average time between events = 1/λ
- Variance = 1/λ²
- Replaces older EXPONDIST function
- Ideal for memoryless processes
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+