In statistics, the **interquartile range **represents the spread of the middle 50% of values in a dataset.

It is calculated as the difference between the 75th percentile (Q3) and the 25th percentile (Q1) of a dataset.

The easiest way to calculate the interquartile range of a dataset in SPSS is to use **Analyze** > **Descriptive Statistics** > **Explore**.

The following example shows how to do so in practice.

**Example: How to Calculate Interquartile Range in SPSS**

Suppose we have the following dataset in SPSS that shows the exam scores received by various students in some class:

Suppose that we would like to calculate the interquartile range for the exam scores.

To do so, click the **Analyze** tab, then click **Descriptive Statistics**, then click **Explore**:

In the new window that appears, drag **Exam_Score** to the **Dependent List **panel:

Then click the **Statistics **button. In the new window that appears, check the box next to **Percentiles **and then click the button next to **Quartiles**:

Then click **Continue**. Then click **OK**.

The following output will appear:

In the **Descriptives** table, we can see that the interquartile range of the exam scores is **10**.

In the **Percentiles** table, we can see that the value at the 25th percentile is **86** and the value at the 75th percentile is **96**.

Thus, here is how the interquartile range was calculated:

- IQR = 75th percentile – 25th percentile
- IQR = 96 – 86
- IQ =
**10**

This matches the value shown in the output.

**Related:** How to Interpret Interquartile Range

**Additional Resources**

The following tutorials explain how to perform other common tasks in SPSS:

How to Calculate a Five Number Summary in SPSS

How to Create a Frequency Table in SPSS

How to Calculate Percentiles in SPSS