Interquartile range

The interquartile range is the span between the twenty-fifth and seventy-fifth percentiles, covering the middle half of the data. It is the box in a box plot and a robust measure of spread.

Also known as IQR. data and analysis · updated 2026-09-08

See also

• Box plot — A box plot summarises a distribution with its quartiles, a median line and whiskers, marking points beyond the whiskers individual…
• Quantile — A quantile is a cut point dividing a distribution into intervals of equal probability. Percentiles and quartiles are quantiles.…

Terms that refer here

Box plot · Outlier · Quantile

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