Quartile Calculator

Calculate first quartile (Q1), second quartile (Q2), third quartile (Q3), and interquartile range (IQR) of your data set

You can paste data from Excel, Google Sheets, or any text document

Minimum

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First Quartile (Q1)

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Second Quartile (Q2)

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Third Quartile (Q3)

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Maximum

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Interquartile Range (IQR)

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Range

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Data Points

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Sorted Data Position

How to Calculate Quartiles

Quartiles divide a ranked data set into four equal parts. The three quartiles are:

  • First Quartile (Q1): The 25th percentile – 25% of data points are below this value
  • Second Quartile (Q2): The 50th percentile (median) – 50% of data points are below this value
  • Third Quartile (Q3): The 75th percentile – 75% of data points are below this value

Calculation Method

  1. Sort your data set from lowest to highest values
  2. Find the median (Q2) of the entire data set
  3. For Q1, find the median of the lower half of the data (excluding Q2 if the data set has an odd number of values)
  4. For Q3, find the median of the upper half of the data (excluding Q2 if the data set has an odd number of values)

Acceptable Data Formats

You can enter data in various formats:

  • Comma separated: 42, 54, 65, 47, 59, 40, 53
  • Space separated: 42 54 65 47 59 40 53
  • New lines: Enter each value on a new line
  • Mixed delimiters: The calculator will automatically detect and process mixed formats

Quartiles

Quartiles mark each 25% of a set of data:

  • The first quartile Q1 is the 25th percentile
  • The second quartile Q2 is the 50th percentile
  • The third quartile Q3 is the 75th percentile

The second quartile Q2 is easy to find. It is the median of any data set and it divides an ordered data set into upper and lower halves.

The first quartile Q1 is the median of the lower half not including the value of Q2. The third quartile Q3 is the median of the upper half not including the value of Q2.

References

[1] Wikipedia contributors. “Quartile.” Wikipedia, The Free Encyclopedia. Last visited 10 April, 2020.