Box and whisker plot maker
Paste a column of numbers, or several columns to compare groups, and the box, the whiskers and the outliers are drawn.
One column per group. Paste from a spreadsheet, or type the numbers separated by commas, spaces or new lines.
Drawing…
| Group | n | Min | Q1 | Median | Q3 | Max | IQR | Outliers |
|---|---|---|---|---|---|---|---|---|
| Class A | 10 | 64 | 73.25 | 83 | 89.5 | 120 | 16.25 | 120 |
| Class B | 10 | 72 | 79.25 | 83.5 | 90.25 | 99 | 11 | none |
How to use it
- Step 1Paste your numbers into the box — one column, straight out of a spreadsheet, or typed with commas between them.
- Step 2To compare groups, paste one column per group with a name in the first row; each column becomes a box of its own.
- Step 3Name the chart and the value axis, then download it as a PNG for a report or an SVG to edit, or press “Share a link” to send the chart itself.
What the box and the whiskers are
A box plot is the five-number summary drawn to scale. The box spans the middle half of the data, from the first quartile to the third; the line across it is the median, not the mean. The whiskers reach out to the furthest values that are still within one and a half interquartile ranges of the box, and anything beyond that is drawn as a separate dot — an outlier by the standard rule, which is a suggestion to look at the value, not a verdict that it is wrong.
Reading one is mostly reading the box. A wide box means the middle half of the data is spread out; a median sitting near one end of the box means the data leans that way; two boxes side by side that barely overlap mean two groups that genuinely differ, which is the comparison this chart is made for.
Which quartiles you get
There is more than one way to find a quartile, and different courses teach different ones. This page uses the definition Excel's PERCENTILE.INC, Google Sheets and most statistical software use: the quartile is interpolated between the two values it falls between. Many American textbooks instead split the data at the median and take the median of each half, which can give a slightly different Q1 and Q3 on small data sets.
Neither is wrong; they are conventions. If your homework expects the textbook method and the box looks a fraction off, that is the reason — the summary table under the chart shows the exact numbers this page used, so the difference is easy to see and to explain.
How many numbers you need
Five or six is enough to draw something honest, and a class set of twenty to forty is where a box plot starts to say something. With three or four values the quartiles sit almost on top of the data points and the box says little that the numbers themselves do not. A column needs at least two values before it is drawn as a box at all.
Questions and answers
How do I make a box and whisker plot online?
Paste your numbers into the box on this page. The quartiles, the median and the outliers are worked out as you type, and the plot is ready to download as a PNG or an SVG.
What counts as an outlier?
The usual rule, and the one used here: anything below Q1 − 1.5 × IQR or above Q3 + 1.5 × IQR, where IQR is the height of the box. Those values are drawn as separate circles and the whiskers stop at the last value inside the fence.
Can I compare two classes on one chart?
Yes — paste one column per class, with the class name in the first row. Each column becomes its own box, drawn against the same scale so the comparison is fair.
Why is the median not in the middle of the box?
Because the data is not symmetrical. The median sits wherever half the values fall below it, so a median close to the bottom of the box means the lower quarter is bunched up and the upper half is stretched out.
Does the box plot show the mean?
Not by default — the line is the median. Tick “Show the mean as a cross” and it is drawn as well, which is a quick way to see how far the average is pulled by extreme values.