Box and Whisker Plot in Excel: Multiple Series

Yes. In Excel for Microsoft 365 on Windows, put each group’s observations in a separate column, include a header for each column, select the data, then choose Insert > Insert Statistic Chart > Box and Whisker. Excel creates a box for each group, letting you compare multiple distributions in one chart.

What multiple series means in a box plot

A box-and-whisker chart summarizes the spread of numerical values. In a chart with multiple series, each series is a separate group of observations and is represented by its own box and whiskers. For example, if you are comparing delivery times for three services, each service’s recorded times should form one group.

For a straightforward layout, put group names in the first row and observations underneath them:

Column A: Standard service, with one delivery time per row.
Column B: Express service, with one delivery time per row.
Column C: Local service, with one delivery time per row.

The headers help Excel label the groups on the chart. Each column supplies the values used to calculate one box; the rows are individual observations, not separate series. If your worksheet instead has groups in rows, you can often use the same data by switching the chart’s row and column orientation.

Prepare the source data

Keep the observations for a group together in one column or row, and use consistent units. A column of delivery times should not mix minutes and hours, for instance. Put descriptive names in the header cells, such as Standard, Express, and Local, rather than leaving the headers empty. Avoid merging cells in the source range because merged headings can make chart data selection harder to interpret.

Each group can have a different number of observations. If one column has fewer values, leave the remaining cells blank; do not enter zero simply to fill the rectangle. A zero is a real numeric observation and can change the distribution, whereas an empty cell is not an observation. Keep notes, text labels, and totals outside the selected data range so Excel does not mistake them for chart input.

A small example might have 12 delivery times for Standard, 10 for Express, and 12 for Local. The chart still has three boxes, even though the Express group has fewer observations. The plot compares the distributions, but it does not automatically make their sample sizes equal or show that the groups have the same amount of data.

Create a chart with several boxes

Arrange the data with one group per column and a header above each group.
Select the entire rectangular range, including the headers and all observations. If your table has other columns, select only the group names and values intended for the chart.
On the ribbon, select Insert > Insert Statistic Chart > Box and Whisker.
Check that the chart shows one box for each group. If Excel has treated rows as groups instead of columns, select the chart and use Chart Design > Switch Row/Column.
Move or resize the chart and add a clear title and axis titles if they will help readers understand the units and groups.

If you add a heading row above the actual table, do not include that extra heading in the chart selection unless you intend it to be part of the chart data. When Excel has selected the wrong range, use Chart Design > Select Data to review or adjust the source. Selecting a clean range before inserting the chart is usually the simplest approach.

Format quartiles, outliers, and averages

To change how the boxes are calculated or displayed, right-click one of the boxes and choose Format Data Series. In the Format Data Series pane, open Series Options. Depending on what you want to communicate, you can adjust the quartile calculation, show outlier points, show inner points, show a mean marker, or show a mean line. The options apply to the selected data series; check other groups too if you want their settings to match.

Excel provides Inclusive median and Exclusive median choices for quartile calculation. These methods can give different quartile boundaries, particularly with small samples, so the height of a box may change when you switch methods. For a comparison between groups, use the same setting for every series and state the choice when the method matters to your readers.

Outlier points are observations that fall beyond the whiskers under the chart’s outlier rule. Showing inner points can reveal the individual observations inside the whiskers, which is useful with small datasets but may make a chart crowded with large ones. A mean marker or line adds the arithmetic average; it is separate from the median, which is the line inside the box. Use these options to answer a specific question rather than turning on every marker by default.

For chart labels, select Chart Design > Add Chart Element to add or change items such as a chart title or axis titles. A vertical axis title such as Delivery time (minutes) can prevent readers from confusing units. A concise chart title should identify the measure and, where useful, the population or period represented.

How to read each box and whiskers

The line inside a box is the median, or middle value when observations are ordered. The bottom and top of the box mark the first and third quartiles. The box therefore covers the middle half of the observations, and its height is the interquartile range: the third quartile minus the first quartile. A taller box indicates more spread across that central half of the data.

In Excel’s box-and-whisker chart, whiskers extend to the most extreme values that are not classified as outliers. Points beyond the whiskers are shown separately when outlier points are enabled. This means a whisker does not necessarily reach the smallest or largest value in the dataset. A common misconception is that every whisker always represents the full minimum-to-maximum range; check for separate outlier points before making that claim.

Compare the boxes’ positions as well as their sizes. If one group’s median is higher, its typical value is higher on the chart’s scale. If its box is wider or taller, its middle observations are more spread out. Outliers may signal unusual cases or data errors, but a chart alone cannot tell you which explanation is correct.

Unequal sample sizes and missing observations

Box plots are useful when group sizes differ, but the graphic does not make the difference disappear. A box is based on the observations available for that group, so a group with 8 values and one with 80 values can each appear as a single box. Consider reporting the sample size alongside the chart, especially when readers might assume the groups are equally well represented. Excel does not automatically add an observation count to each box.

Leave genuinely missing observations blank rather than replacing them with zero or a guessed value. Check that blanks are truly missing data and not an accidental gap in an otherwise complete record. If an entire group has no numeric values, it cannot provide a meaningful distribution. Also verify that values stored as text have been converted to numbers where appropriate; text-formatted numbers may not behave as expected in a statistical chart.

Add, remove, or reorder a series

To include another group, the most reliable method is to extend the selected source range to include its header and observations. You can also select the chart and open Chart Design > Select Data to inspect its source and make changes. The dialog’s controls can vary with the chart and worksheet layout, so check the series name and value range after editing. If the new group appears as points or labels in an unexpected place, undo the edit and select the complete intended data range again.

To remove a group, exclude its column or row from the chart’s source data, or remove its series through Select Data. To change the order of groups, adjust the order of the source columns or use the series controls in Select Data where available. After any change, confirm that the axis labels still match the right observations; a chart can look plausible even when a group name is paired with the wrong data.

Common problems and fixes

Only one box appears: Confirm that the selected range includes multiple groups and that each group has its own column or row. If the chart orientation is reversed, use Chart Design > Switch Row/Column.
Group names are missing: Include the header cells in the source selection, then check the data source in Chart Design > Select Data.
Zeros appear unexpectedly: Look for zeros entered as placeholders for missing values. Replace them with blanks only when the observations are genuinely missing.
The boxes do not match another tool’s quartiles: Compare the quartile method and confirm both tools use the same observations. Different quartile conventions can produce different box boundaries.
The chart looks crowded: Consider turning off inner points, widening the chart, or reducing unnecessary labels. Keep outlier points visible if identifying unusual values is part of the chart’s purpose.
A group is absent or oddly represented: Check for empty groups, text in the values, a selection that stops too early, or accidental inclusion of totals and notes.

In Excel for Mac, box-and-whisker charts are available in supported desktop editions, but ribbon placement can differ slightly with the app version and ribbon layout. Look on the Insert tab for the statistical chart options, then use the chart design and formatting controls to adjust the source and series. Excel for the web may not expose every chart-creation or formatting control available in desktop Excel; if a setting is missing, open the workbook in the desktop app.

When a box plot is the right choice

A box plot is a compact way to compare medians, central spread, and unusual values across several groups. It is especially useful when there are many observations per group and showing every value in a table would make comparison difficult. It does not show the full shape of a distribution as clearly as a histogram, and two groups can have similar boxes while differing in clustering or gaps among their values.

For a small dataset, a dot plot or a chart that displays every observation may be easier to interpret. A column chart is usually a poor substitute if the goal is to compare distributions: a single bar commonly emphasizes an aggregate such as a sum or average and can hide variation. Choose the chart based on the question, and provide sample sizes or a brief note if they affect interpretation.

Frequently Asked Questions

Can I put multiple box-and-whisker plots on one Excel chart?
Yes. Put each group’s numeric observations in a separate column or row, include group headers, select the data, and insert a Box and Whisker chart. Excel draws a separate box for each group.

Should each group go in a row or a column?
Columns are a convenient default: one group per column, with observations below its header. If your groups are in rows, create the chart and try Chart Design > Switch Row/Column if Excel interprets the layout the wrong way.

Can groups have different numbers of values?
Yes. Leave unused cells blank for the shorter groups; do not fill them with zeros. The chart can plot groups with unequal sample sizes, but you may want to show or report each group’s count separately.

Why does Excel show different quartiles from another program?
Quartile calculation conventions differ. In Format Data Series, check whether Excel is set to Inclusive median or Exclusive median, and compare that choice with the method used by the other program.

Do the whiskers always show the minimum and maximum?
No. Values classified as outliers can appear as separate points beyond the whiskers. The whiskers reach the most extreme non-outlier values under the chart’s rule, so inspect the plotted points before describing the full range.

Try it: the Date Difference Calculator: days, months, years and weekdays between two dates, with the DATEDIF formulas.

More in How-to basics

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

Spotted an error in this guide? Let us know.