A **cumulative distribution function (CDF) **describes the probability that a random variable takes on a value less than or equal to some number.

We can use the following function in Excel to calculate cumulative distribution probabilities:

=NORM.DIST(x, MEAN, STANDARD_DEVIATION, TRUE)

The following example shows how to calculate and plot a CDF in Excel.

**Example: Calculate & Plot CDF in Excel**

First, let’s create the following dataset in Excel:

Next, let’s specify the mean and standard deviation of the distribution:

Next, we can calculate the cumulative distribution probability for the first value in the dataset by using the following formula:

=NORM.DIST(A2, $F$1, $F$2, TRUE)

Next, we can copy and paste this formula down to every other cell in column B:

The CDF is now complete. The way we interpret the values is as follows:

- The probability that the random variable will take on a value equal to or less than 6 is .
**00135**. - The probability that the random variable will take on a value equal to or less than 7 is .
**00383**. - The probability that the random variable will take on a value equal to or less than 8 is .
**00982**.

And so on.

To visualize this CDF, we can highlight every value in column B. Then, we can click the **Insert** tab along the top ribbon and click **Insert Line Chart** to produce the following chart:

The values along the x-axis show the values from the dataset and the values along the y-axis show the CDF values.

**Additional Resources**

CDF vs. PDF: What’s the Difference?

How to Make a Bell Curve in Excel

How to Calculate NormalCDF Probabilities in Excel