Third Quartile Calculator

The third quartile, Q3, is the 75th percentile of a data set. It is the value that separates the highest 25% of data from the lower 75%. Q3 is found by taking the median of the upper half of the ordered data set, not including the overall median (Q2).

First, sort your data in ascending order. Find Q2 (the median) of the full data set. Then Q1 is the median of the lower half (below Q2), and Q3 is the median of the upper half (above Q2). If the data set has an odd number of values, the middle value is excluded when computing Q1 and Q3.

The interquartile range (IQR) measures statistical dispersion and is calculated as IQR = Q3 − Q1. It represents the spread of the middle 50% of your data and is resistant to outliers, making it a useful measure of variability.

Q2 and the median are the same value. The second quartile (Q2) is the 50th percentile, which is by definition the median of the data set. It divides the ordered data into an equal lower half and upper half.

The minimum is simply the smallest value in the data set, and the maximum is the largest. After sorting your data in ascending order, the first value is the minimum and the last value is the maximum.

The range is the difference between the maximum and minimum values in a data set: Range = Maximum − Minimum. It gives a simple measure of total spread, though it is sensitive to outliers since it only considers the two extreme values.

You can enter numbers separated by commas, spaces, or new lines. You can also paste data directly from a spreadsheet or text document. The calculator will parse all numeric values and ignore any non-numeric separators.

For an even-numbered data set, the median (Q2) falls between the two middle values, and each half has an equal number of data points for computing Q1 and Q3. For an odd-numbered data set, the middle value is the median and is excluded from both halves before computing Q1 and Q3.