Box and Whisker Plot Labeled – Median, Quartiles, Whiskers

All 11 parts on the diagram

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The five numbers 5

Minimum The smallest value in the data set. The left whisker ends here, at 3.
First quartile (Q1) The lower half of the data's median. It is the box's left side, here at 6. Also called the lower quartile.
Median The middle value of the data set. Half of the values lie on each side of it. Here it is 10.
Third quartile (Q3) The upper half of the data's median. It is the box's right side, here at 16. Also called the upper quartile.
Maximum The largest value in the data set. The right whisker ends here, at 19.

Box, whiskers and line 3

Box The box holds the data's middle half. It runs from the first quartile to the third quartile.
Whiskers The two lines that run out from the box. One reaches the minimum and the other the maximum.
Number line The plot is drawn above this line of numbers. Each of the five numbers is read off it. It is also called the axis.

Spread and outlier 3

Interquartile range How far the first quartile is from the third. It is the length of the box: here 12 − 6 = 6.
Range The largest value minus the smallest value. The outlier is the largest value here, so the range is 24 − 4 = 20.
Outlier A value far from the rest of the data. It is drawn as a point past the end of the whisker.

How this list was compiled: Every name was read on 2026-10-03 in at least two of these. (1) Wikipedia, English edition, Box plot, https://en.wikipedia.org/wiki/Box_plot (the five-number summary: minimum, maximum, median, first and third quartiles, also called the lower and upper quartile; the box drawn from Q1 to Q3 with a line at the median; the lines called whiskers; the interquartile range as the gap from lower to upper quartile; whiskers within 1.5 IQR and the other points plotted as outliers), and Range (statistics), https://en.wikipedia.org/wiki/Range_(statistics) (largest value minus smallest value). (2) Statistics Canada, Statistics: Power from Data!, 4.5.2 Visualizing the box and whisker plot, https://www150.statcan.gc.ca/n1/edu/power-pouvoir/ch12/5214889-eng.htm, and 4.5.1 Calculating the range and interquartile range, https://www150.statcan.gc.ca/n1/edu/power-pouvoir/ch12/5214890-eng.htm (minimum, lower quartile Q1, median Q2, upper quartile Q3, maximum; the sides of the box are the quartiles and the box covers 50% of the data; the whiskers are the two lines beyond the box; an axis that indicates the values; the range is the maximum less the minimum and grows when an extreme value is added; points past 1.5 times the interquartile range drawn as potential outliers). (3) NIST/SEMATECH e-Handbook of Statistical Methods, 1.3.3.7 Box Plot, a United States government work, https://www.itl.nist.gov/div898/handbook/eda/section3/boxplot.htm (median, lower and upper quartiles, the box as the middle 50% of the data, lines to the minimum and maximum points, the interquartile range, outliers). (4) California Department of Education, California Common Core State Standards: Mathematics, https://www.cde.ca.gov/be/st/ss/documents/ccssmathstandardaug2013.pdf (grade 6: data displayed in plots on a number line, including box plots; glossary: box plot, first quartile, third quartile, interquartile range; a note that many methods for computing quartiles are in use). (5) An open-license grade 6 lesson on box plots, https://im.kendallhunt.com/MS/students/1/8/16/index.html (a box plot shows data along a number line; a whisker runs from Q1 to the minimum and from Q3 to the maximum; the box is the data's middle half). Hints, detail lines and both data sets are our own. Licence: own work

The drawing: Drawn for this site by script, 2026-10-03. Own work. Licence: own work

How it works

This box and whisker plot labeled with its five numbers shows the minimum, first quartile, median, third quartile and maximum above a number line. A second plot adds the interquartile range, the range and an outlier.

Read the full guide

Read the five numbers

The five numbers run left to right: minimum, first quartile, median, third quartile, maximum. A dashed line drops from each to its value on the number line: 3, 6, 10, 16 and 19. The box holds the middle half of the made-up data, and a whisker runs from each side of it.

Spread and outlier

The second plot has one value far to the right, drawn as a dot: an outlier. The bracket over the box is the interquartile range and the long bracket under the plot is the range. For a box and whisker labeled answer key, print the page with its names.

The median is not always in the middle of the box. It sits wherever the middle value falls.

Questions and answers

What are the parts of a box and whisker plot?

A box that runs from the first quartile to the third quartile, a line inside the box at the median, and two whiskers that run out to the minimum and the maximum. The plot is drawn above a number line.

What is the five-number summary?

The minimum, the first quartile, the median, the third quartile and the maximum of a data set. A box plot is a drawing of these five numbers.

How do you find the quartiles for a box plot?

Put the values in order and find the median. The median of the values below it is the first quartile, and the median of the values above it is the third quartile. Other methods are in use and can give slightly different quartiles.

What is an outlier on a box plot?

A value far from the rest of the data. A common rule draws any value more than 1.5 times the interquartile range past the box as a point of its own, and the whisker stops at the last value inside that distance.