Identify the median line inside the box
Identify the lower edge of the box as the first quartile
Identify the upper edge of the box as the third quartile
Read the box height as the interquartile range
Read the whiskers as the spread outside the middle 50%
Check the whisker ends for minimum and maximum values
Look for outliers plotted beyond the whiskers
Compare median positions to judge skewness
Compare box and whisker lengths to judge variability
Compare multiple boxplots by median, spread, and outliers