Quartile deviation is usually considered a measure of dispersion. Quartiles are the values, which divide the numerical data into three sections such as Q1, Q2, and Q3. The middle section of the three sections determines the central point of the distribution and displays the values that are located nearby to the midpoint. Here, the central value is referred to as a median. When it comes to its calculation then, it might take some time because quartiles are difficult to calculate. But you can use the online upper quartile calculator by calculator-online.net that determines Q1, Q2, Q3, and interquartile range from the data set.

**What is Quartile Deviation?**

Quartile deviation is the difference of the upper, lower, and middle quartile in the frequency distribution. The difference between the quartiles is called the interquartile range, and that difference is divided by two. When one takes half of the difference between the third and first quartile for a simple distribution then, the frequency distribution is said to be the quartile deviation. No doubt, the manual calculation becomes a daunting task for the person that is not good at doing the calculation. Well! with the support of the upper & third quartile calculator anyone can calculate all types of quartiles without any error.

**Quartile Deviation Formula:**

The quartile deviation formula is usually used in statistics to determine, spread or measure the dispersion. Which is said to be the semi-inter-quartile range.

**Q.D Formula = **Q3-Q12

- In the formula, Q3 and Q3 are used in the quartile deviation calculation, which is 25 percent of upper & lower quartile data. It displays the measures of dispersion or spread when the difference of the quartiles is calculated.
- For the quartile deviation, you need to calculate the Q1 and also find the Q3. After finding the Q1 and Q3 make a difference of both and then divide it by 2.

This is one of the easiest ways to measure the dispersion for the open-ended data. Instead of using this formula to find the quartile deviation, use the quartile calculator. The online calculator figures out the median, lowest, and greater values and also the total of the given data set.

**Finding Quartile Deviation in Excel:**

- The very first step of finding the quartile deviation in excel is to enter the data set in a single column of the excel sheet. For example, you are going to type the data set in the cells from A1 to A10’
- Now, you need to click on any of the empty cells of the excel sheet.
- If you want to find the first quartile then, you have to type “=QUARTILE(A1:A10,1)” and hit the enter.
- Just like this, you need to type “=QUARTILE(A1:A10,3)” to find the third quartile.

So, these are the steps you need to perform on the Excel sheet to find the quartile deviation in Excel. If it seems difficult to you then, don’t worry about the calculation. Give a try to an online quartile calculator that helps you to find the Q1, Q2, and Q3 in the blink of an eye.

**Conclusion:**

Thankfully by reading this post you came to know how to calculate the quartile deviation in Excel. As you know this guidepost is particularly about the calculation of Q.D in Excel that is why we have mentioned the basic steps that are required to perform for the quartile deviation calculation. We have also mentioned a standard formula for determining the semi-interquartile range manually. There are times when you find its calculation complex at that time you can use the free online quartile calculator to make your calculation easier. The calculator not only measures the dispersion of data but also shows the sum of the quartiles.