Math · Statistics

IQR Calculator

Find the interquartile range of any dataset, get Q1, median and Q3, and spot outliers using the 1.5×IQR rule — with a box plot.

Dataset (comma or space separated)

Interquartile range (IQR = Q3 − Q1)

Q1 (25th percentile)

Median Q2 (50th)

Q3 (75th percentile)

Data count

Outliers detected

Definition: IQR = Q3 − Q1, the middle 50% of the data.
Quartiles: computed by linear interpolation (same as PERCENTILE.INC): position = (n − 1)·p + 1.
Outlier rule: a value is an outlier if x < Q1 − 1.5·IQR or x > Q3 + 1.5·IQR.

Robust spread measure

IQR is unaffected by extreme values, unlike the range.

Box plot

Visualize minimum, Q1, median, Q3 and maximum at a glance.

Outlier detection

Flag suspicious values with the standard 1.5×IQR fence.

Instant analysis

Paste any list — results recalculate as you type.

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