Box Plot Generator
Create a box-and-whisker plot to visualize data distribution.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Box Plot Generator
Enter at least 4 data values separated by commas or spaces. The tool draws a box-and-whisker plot on a canvas, showing the box from Q1 to Q3, a median line in orange, whiskers extending to the most extreme non-outlier values, and outlier dots beyond the fences. The breakdown shows all five-number summary values plus IQR and outliers.
About Box Plots
Box plots (box-and-whisker plots) were introduced by John Tukey in 1970. They provide a visual summary of a dataset's distribution in one compact graphic. The box represents the interquartile range (middle 50%), the line inside is the median, and whiskers extend to the farthest data points within 1.5 times the IQR. Points beyond the whiskers are plotted individually as outliers. Box plots are ideal for comparing distributions across groups.
Frequently Asked Questions
What do the dots outside the whiskers mean?
Dots beyond the whiskers are outliers, values more than 1.5 times the IQR away from Q1 or Q3. They represent unusually extreme values in the dataset.
Why does the median line not always appear centered in the box?
The median line is positioned at the actual median value, which only appears centered when Q1 and Q3 are equidistant from it. An off-center median indicates skewness in the data.
How many data points do I need for a meaningful box plot?
A minimum of 4 values is required to compute quartiles. For a box plot to be meaningful, 10 or more values is recommended. With very few values, the quartile positions may not accurately reflect the distribution.