Math · Statistics

Quartile Calculator

Find Q1, Q2 (median), Q3, the interquartile range and outliers — with a live box plot of your data.

Box plot
IQR: Q3 − Q1    Fences: Q1 − 1.5×IQR and Q3 + 1.5×IQR
Outlier rule: any value below the lower fence or above the upper fence is flagged as a potential outlier.

All five numbers

Min, Q1, median, Q3, max — the classic five-number summary.

Outlier detection

Values beyond 1.5×IQR fences are highlighted.

Live box plot

Interactive box-and-whisker chart drawn with pure HTML.

Two methods

Median-of-halves and inclusive interpolation methods.

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