Quartile Calculator
Compute the first (Q1), second (median, Q2), and third (Q3) quartiles of a dataset, along with interquartile range (IQR).
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Quartile Calculator
This calculator computes the first quartile (Q1), median (Q2), third quartile (Q3), and interquartile range (IQR) from a set of numbers.
- Enter your data: Type numbers separated by commas or spaces (e.g.,
1, 2, 3, 4, 5or10 20 30). - Click "Calculate" to get results.
- Read the output:
- Q1 – median of the lower half of sorted data.
- Median (Q2) – middle value of the entire dataset.
- Q3 – median of the upper half.
- IQR – difference between Q3 and Q1 (measure of spread).
Note: Requires at least two numbers. For even-length halves, the median is the average of the two middle numbers. All results are rounded to two decimal places.
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Frequently Asked Questions
Quartiles divide a dataset into four equal parts. Q1 is the median of the lower half, Q2 is the overall median, and Q3 is the median of the upper half.
When the number of data points is even, the median is the average of the two middle numbers after sorting.
IQR (Interquartile Range) is the difference between Q3 and Q1. It measures the spread of the middle 50% of the data.
