# EXPON.DIST Function in Microsoft Excel

## Part 1: Introduction

### Definition

The EXPON.DIST function in Microsoft Excel returns the exponential distribution.

### Purpose

The EXPON.DIST function models the time between events, such as how long an automated bank teller takes to deliver cash. For example, you can use EXPON.DIST to determine the probability that the process takes at most 1 minute.

### Syntax & Arguments

The syntax for the EXPON.DIST function is as follows:

syntax
```EXPON.DIST(x, lambda, cumulative) ```

The EXPON.DIST function syntax has the following arguments:

• x: Required. The value of the function.
• lambda: Required. The parameter value.
• cumulative: Required. A logical value that indicates which form of the exponential function to provide. Suppose cumulative is TRUE, EXPON.DIST returns the cumulative distribution function; if FALSE, it returns the probability density function.

### Return value

The EXPON.DIST function returns the exponential distribution.

### Remarks

• If x or lambda is nonnumeric, EXPON.DIST returns the #VALUE! Error value.
• If x < 0, EXPON.DIST returns the #NUM! Error value.
• If lambda ≤ 0, EXPON.DIST returns the #NUM! Error value.

## Part 2: Examples

Let’s look at some examples of how to use the EXPON.DIST function in Microsoft Excel in a business context.

### Example 1

Purpose: To calculate the cumulative exponential distribution function for the time it takes to process an order.

ABC
1Time to ProcessFormulaResult
20.2=EXPON.DIST(A2, 10, TRUE)0.86466472
30.3=EXPON.DIST(A3, 10, TRUE)0.95021293
40.4=EXPON.DIST(A4, 10, TRUE)0.98168436

In this example, we’re using the EXPON.DIST function to calculate the cumulative exponential distribution function for the time it takes to process an order. The lambda parameter value is 10.

### Example 2

Purpose: To calculate the probability exponential distribution function for the time it takes to process an order.

ABC
1Time to ProcessFormulaResult
20.2=EXPON.DIST(A2, 10, FALSE)1.35335283
30.3=EXPON.DIST(A3, 10, FALSE)0.90483742
40.4=EXPON.DIST(A4, 10, FALSE)0.67032005

In this example, we’re using the EXPON.DIST function to calculate the probability exponential distribution function for the time it takes to process an order. The lambda parameter value is 10.

### Example 3

Purpose: To calculate the cumulative exponential distribution function for the time it takes to deliver a product.

ABC
1Time to DeliverFormulaResult
20.5=EXPON.DIST(A2, 5, TRUE)0.99326205
30.6=EXPON.DIST(A3, 5, TRUE)0.99752125
40.7=EXPON.DIST(A4, 5, TRUE)0.99908812

In this example, we’re using the EXPON.DIST function to calculate the cumulative exponential distribution function for the time it takes to deliver a product. The lambda parameter value is 5.

### Example 4

Purpose: To calculate the probability exponential distribution function for the time it takes to deliver a product.

ABC
1Time to DeliverFormulaResult
20.5=EXPON.DIST(A2, 5, FALSE)0.60653066
30.6=EXPON.DIST(A3, 5, FALSE)0.54881164
40.7=EXPON.DIST(A4, 5, FALSE)0.49658530

In this example, we’re using the EXPON.DIST function to calculate the probability exponential distribution function for the time it takes to deliver a product. The lambda parameter value is 5.

### Example 5

Purpose: To calculate the cumulative exponential distribution function for the time it takes to process a transaction.

ABC
1Time to ProcessFormulaResult
20.1=EXPON.DIST(A2, 15, TRUE)0.77686984
30.2=EXPON.DIST(A3, 15, TRUE)0.95021293
40.3=EXPON.DIST(A4, 15, TRUE)0.99326205

In this example, we’re using the EXPON.DIST function to calculate the cumulative exponential distribution function for the time it takes to process a transaction. The lambda parameter value is 15.

### Example 6

Purpose: To calculate the cumulative exponential distribution function for processing an order and use the IF function to determine if the process is efficient (less than 0.5).

ABCD
1Time to ProcessFormulaResultEfficiency
20.2=EXPON.DIST(A2, 10, TRUE)0.86466472=IF(C2<0.5, “Inefficient”, “Efficient”)
30.3=EXPON.DIST(A3, 10, TRUE)0.95021293=IF(C3<0.5, “Inefficient”, “Efficient”)
40.4=EXPON.DIST(A4, 10, TRUE)0.98168436=IF(C4<0.5, “Inefficient”, “Efficient”)

In this example, we’re using the EXPON.DIST function to calculate the cumulative exponential distribution function for the time it takes to process an order. The lambda parameter value is 10. We then use the IF function to determine if the process is efficient (less than 0.5).

### Example 7

Purpose: To calculate the probability exponential distribution function for the time it takes to process an order and use the SUM function to get the total probability.

ABCD
1Time to ProcessFormulaResultTotal Probability
20.2=EXPON.DIST(A2, 10, FALSE)1.35335283=SUM(C2:C4)
30.3=EXPON.DIST(A3, 10, FALSE)0.90483742=SUM(C2:C4)
40.4=EXPON.DIST(A4, 10, FALSE)0.67032005=SUM(C2:C4)

In this example, we’re using the EXPON.DIST function to calculate the probability exponential distribution function for the time it takes to process an order. The lambda parameter value is 10. We then use the SUM function to get the total probability.

### Example 8

Purpose: To calculate the cumulative exponential distribution function for the time it takes to deliver a product and use the VLOOKUP function to find the result for a specific time.

ABCD
1Time to DeliverFormulaResultLookup Result
20.5=EXPON.DIST(A2, 5, TRUE)0.99326205=VLOOKUP(0.6, A2:C4, 3, FALSE)
30.6=EXPON.DIST(A3, 5, TRUE)0.99752125=VLOOKUP(0.6, A2:C4, 3, FALSE)
40.7=EXPON.DIST(A4, 5, TRUE)0.99908812=VLOOKUP(0.6, A2:C4, 3, FALSE)

In this example, we’re using the EXPON.DIST function to calculate the cumulative exponential distribution function for the time it takes to deliver a product. The lambda parameter value is 5. We then use the VLOOKUP function to find the result for a specific time (0.6).

## Part 3: Tips and Tricks

• The EXPON.DIST function helps model the time between events.
• Remember that the EXPON.DIST function will return an error if x or lambda is non-numeric, if x is less than 0, or if lambda is less than or equal to 0.
• You can use the EXPON.DIST functions with other functions like IF, SUM, VLOOKUP, etc., to perform more complex calculations.