Box Plot in Excel: How to Chart Multiple Data Series

Yes. In Excel for Microsoft 365 on Windows, put each group of numeric observations in its own column, select the data, then choose Insert > Insert Statistic Chart > Box and Whisker. Excel creates a box plot with one box for each column, letting you compare several distributions in the same chart.

What a multiple-series box plot shows

A box plot, also called a box-and-whisker chart, summarizes how values in a group are distributed. The box marks the lower and upper quartiles, with a line for the median; whiskers show the range of values within Excel’s whisker rule. Depending on the chart settings, individual observations and outliers can also appear as points. A box plot is useful when you want to compare spread, typical values, and unusually high or low observations without displaying every value as a separate chart mark.

In this chart, a “series” is a group of observations that gets its own box. For example, if you compare delivery times for three shipping methods, each method should have its own column of times. Excel plots three boxes, one per method. The boxes can have different numbers of observations, which is useful when sample sizes are unequal, provided the cells contain the actual observations rather than summary statistics.

A box plot is not a chart of averages alone. Two groups can have similar medians but very different spreads, or similar spreads but different medians. Looking at multiple boxes side by side makes those differences easier to spot than comparing only the group means.

Arrange the source data before charting

For the clearest setup, use one column per group, with a short heading in the first row and individual numeric observations below it. For example, columns might be headed Method A, Method B, and Method C, with each delivery time entered on a separate row. Keep the headings descriptive because Excel uses them as series names in the chart legend or category labels.

Use one observation per cell; do not enter a median, average, or quartile summary in place of the raw data.
Keep the values numeric. Text such as units typed into the value cells can interfere with charting; put units in the heading or axis title instead.
Leave missing observations blank rather than entering zero. A zero is a real numeric value and can change the distribution.
Use a consistent unit and measurement definition for all groups being compared.
Give each column a unique heading and avoid merged cells in the data range.

Groups do not have to contain the same number of observations. If Method A has 20 recorded times and Method B has 17, you can leave the remaining cells in Method B blank. Check the chart after insertion to make sure the blanks have not been replaced by zeros or included as unintended values.

Create the chart in Excel for Microsoft 365

Arrange the observations in adjacent columns and include the column headings.
Select the full data range, including the headings. If the columns are not next to each other, create a contiguous chart-ready table first; selecting nonadjacent ranges can make the series arrangement harder to control.
On the ribbon, select Insert > Insert Statistic Chart > Box and Whisker.
Check that Excel has made one box for each group. If it instead treats rows as groups, select the chart and use Chart Design > Switch Row/Column.
Add or edit the chart title, axis titles, legend, and formatting as needed. Select the chart to display the chart-specific ribbon tabs.

If you do not see the Box and Whisker option, confirm that you are using a supported desktop version of Excel and that the chart insertion menu is open. Box-and-whisker charts are available in Excel 2016 and later desktop versions, including Microsoft 365. Excel for the web and other editions may have different chart-creation or formatting controls, so use the desktop app when a setting described here is missing.

Control the boxes, points, and whiskers

To adjust how the chart displays the observations, right-click a box and choose Format Data Series. In the formatting pane, open Series Options. The available options include displaying outlier points, displaying inner points, showing mean markers, showing a mean line, choosing the quartile calculation, and changing the gap width between boxes. Some controls are easier to identify after selecting the series rather than the chart background.

Show outlier points: displays individual values that Excel classifies as outliers under its box-plot rule. An outlier marker is a statistical flag, not proof that a measurement is wrong.
Show inner points: displays observations between the whisker limits, which can reveal clusters or gaps but may make a chart crowded.
Show mean markers or mean line: adds the arithmetic mean, which can differ noticeably from the median when a distribution is skewed.
Gap width: changes the spacing between boxes. Narrower gaps can help when comparing many groups, but too little spacing makes labels and boxes harder to distinguish.

Excel’s whiskers do not necessarily extend to the smallest and largest values. In the conventional box-plot interpretation, whiskers extend to the most extreme observations within the outlier limits, and values beyond those limits are plotted separately when outliers are shown. The displayed points and whiskers therefore provide more information than a simple minimum-to-maximum range.

Choose a quartile calculation consistently

Excel offers inclusive and exclusive median choices under the series’ quartile calculation options. These methods can produce different quartile boundaries, particularly in small samples, so two charts made from the same observations may not have identical boxes if they use different settings. The distinction concerns how the median is handled when calculating the lower and upper halves of the data.

There is not one setting that is automatically right for every purpose. If a class, workplace, scientific field, or reporting standard specifies a quartile convention, use that convention. Otherwise, choose a method deliberately and apply it consistently across every group and every chart you intend to compare. If a reader needs to reproduce the result, note the setting in a chart note or accompanying documentation.

Do not confuse the box-plot quartile setting with the chart’s mean marker. Quartiles describe positions in the ordered observations; the mean is the arithmetic average. A long tail or a few extreme values can pull the mean away from the median, which is why the two markers may not align.

Fix common multiple-series problems

If Excel creates one box instead of several, check the selected range and its orientation. A single column of values is normally one group. Put each group in a separate column, include a heading for each, and use Chart Design > Switch Row/Column if Excel has interpreted the layout the other way around.

If the legend shows generic names such as Series 1, Excel may not have recognized the heading row. Recheck that the headings were included in the selection and are directly above their observations. You can also use Chart Design > Select Data to inspect the chart’s source range and series names.

If a box looks unexpectedly compressed, investigate the data before changing the chart design. One extreme value can expand the value axis and make the other boxes appear small. Check for misplaced decimals, inconsistent units, accidental zeros, or observations from a different population. You can format the vertical axis to adjust its displayed bounds, but do not hide meaningful values merely to make the chart look more balanced.

If the chart is crowded, reduce the number of groups shown at once, widen the chart, shorten category names, or turn off inner points. Rotating or shortening labels can help, but avoid removing the group names entirely. For a fair comparison, keep the same axis scale across charts that readers are expected to compare.

When a box plot is the right chart

Use a box plot when the question is about comparing distributions: Which group has the higher median? Which has more variation? Are there unusually distant observations? It is especially useful for larger datasets where showing every observation in a bar chart would obscure the distribution.

A bar chart is often clearer when the main message is a single total or average per category, but it hides much of the distribution. A histogram shows the shape of one distribution in more detail, while several histograms can be awkward to compare because their bars overlap or require separate panels. A dot plot or strip plot shows individual values more directly, which can be preferable for small samples. A box plot is a compact summary, not a substitute for the raw data when sample size is small or the distribution’s shape matters.

Be cautious when sample sizes differ greatly. The boxes summarize quartiles but do not, by themselves, communicate how many observations each group contains. State sample sizes in labels, notes, or a nearby table when that context matters. Also avoid treating overlapping boxes as a formal significance test: a visual comparison is not the same as an inferential statistical analysis.

Frequently Asked Questions

Can I put multiple box plots on one Excel chart?
Yes. Put each group’s raw observations in a separate column, select the columns with their headings, and insert a Box and Whisker chart. Excel makes a box for each data series.

Can the groups have different numbers of values?
Yes. Each column can contain a different number of observations. Leave unused cells blank, not zero, and check that the chart reflects the intended groups.

How do I change the order of the boxes?
Reorder the source columns and headings, or inspect the series and category arrangement through Chart Design > Select Data. The chart order follows its source-data setup, so keeping the table in the intended display order is usually simplest.

Why does Excel show outlier dots?
Excel can display points beyond the whisker limits as outliers. They may be valid observations, recording errors, or values from a different process; investigate them rather than deleting them automatically. You can toggle their display in Format Data Series > Series Options.

Can I make a box plot from a table with a group column and a value column?
That long-format layout is useful for analysis, but the standard Excel box-and-whisker chart is easiest to build when each group’s observations are in its own column. Reshape the values into separate group columns first, taking care not to discard or misassign records.

Why are my quartiles different from another program’s?
Programs can use different quartile conventions, and Excel itself lets you choose inclusive or exclusive median calculations. Compare the methods and settings, not just the chart appearance, before concluding that either result is wrong.

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Sources: Function behaviour and menu paths: Microsoft Support documentation for Excel. Method & sources

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