Box Plot Maker

Paste one column per group, get a Tukey box plot and five-number summary.

Paste one column of numbers per group. The tool draws a Tukey box plot: the box spans Q1 to Q3 with a line at the median, whiskers reach the furthest points within 1.5 times the IQR, and points beyond are shown as outliers. Quartiles use linear interpolation, the same method as R type 7, numpy and Excel QUARTILE.INC.

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What you get

Questions

How do you make a box and whisker plot?

Sort the data, find the first quartile, median and third quartile, and draw a box from Q1 to Q3 with a line at the median. Whiskers extend to the most extreme values within 1.5 times the IQR from the box. Paste your numbers here and this is done for you.

How are outliers defined in a box plot?

A value is an outlier if it is below Q1 minus 1.5 times the IQR or above Q3 plus 1.5 times the IQR, where IQR is Q3 minus Q1. This is Tukey's rule and it is the default in R, Python and GraphPad Prism.

Why do my quartiles differ from another calculator?

There are several quartile methods. This tool uses linear interpolation, R type 7, which matches numpy, R quantile(), and Excel QUARTILE.INC. Excel QUARTILE.EXC and some textbooks use other methods and give slightly different values on small samples.

What is the five-number summary?

Minimum, first quartile, median, third quartile and maximum. The table under the plot lists these for each group, plus n, mean, IQR and any outliers.

Should I show the data points on a box plot?

For small samples, yes. Many journals now ask for individual points, because a box plot of 5 values can hide the distribution. Turn on Show all points to overlay them.

More Data Visualization

All free tools · By Dr. Zubair Khalid, DVM, MS, PhD.