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Quartile Calculator

Enter a list of numbers to find Q1, the median, Q3 and the interquartile range.

Separate the numbers with commas, spaces or new lines. They need not be sorted.

This result is an estimate only. Double-check important figures before relying on them.

How it is calculated

  • Sort the numbers
  • Q1, Q2 and Q3 are the 25th, 50th and 75th percentiles using linear interpolation
  • IQR = Q3 − Q1

For more detail on a single percentile, use the percentile calculator.

Worked example

For 1, 2, 3, 4, 5, 6, 7, 8:

  • Q1 = 2.75, median = 4.5, Q3 = 6.25
  • IQR = 3.5

Why your number may differ

Textbook methods that exclude or include the median when splitting the data can give Q1 and Q3 values that differ from this method, mainly on short lists.

Frequently asked questions

What are quartiles?

They split sorted data into four equal parts. Q1 is the 25th percentile, Q2 the median and Q3 the 75th percentile.

What is the IQR?

The interquartile range is Q3 − Q1, the spread of the middle half of the data. It is not affected by extreme values.

Why does another site give different quartiles?

Several methods exist. This one interpolates linearly like Excel QUARTILE.INC. Methods that split the list in halves can differ slightly.

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