Excel Chart With Two Different Scales: How to Make One

Yes. In Excel for Microsoft 365 on Windows, put one data series on a secondary axis: select the chart, choose Chart Design > Change Chart Type > Combo, and check Secondary Axis beside that series. Excel then displays two vertical scales, each suited to a different series, so the values can be compared in one chart without forcing them onto the same numerical range.

What two scales mean in an Excel chart

A chart with two different scales usually has a primary vertical axis on the left and a secondary vertical axis on the right. Each axis measures a different data series. For example, monthly sales might range from $20,000 to $80,000, while the number of website visits ranges from 5,000 to 25,000. A single scale could make one series appear nearly flat; separate scales let both patterns remain visible.

The secondary axis does not convert, normalize, or otherwise change the underlying values. It changes how Excel maps one series onto the chart area. The values are still the same numbers in the worksheet, but the two axes can use different ranges, units, and intervals. That difference is useful, but it also means that the apparent heights or slopes of the series are not necessarily directly comparable.

A common chart type for this purpose is a combination chart: columns show one measure and a line shows another. The secondary axis is not limited to combination charts, however. You can assign a series to the secondary axis in many chart types, although some combinations may be difficult to read or unavailable for particular chart types.

When a secondary axis is useful

Use two scales when the series are related in a meaningful way but differ substantially in magnitude or units. A typical example is revenue and units sold over time. Both can rise and fall by month, but currency and item counts do not share a useful common scale. A second example is temperature and rainfall, where one series is measured in degrees and the other in millimeters.

A secondary axis can also help when one series has much larger numerical values than another. Suppose a report tracks monthly sales and a conversion rate. Sales might be between $50,000 and $100,000, while conversion is between 2% and 6%. Plotting both against a single axis may compress the percentage series toward the bottom of the chart.

Consider whether the series actually belong together before adding an axis. A shared timeline, subject, or business question can justify putting them in one visual. Two unrelated measures do not become meaningfully comparable just because they fit in the same chart. If a reader would have to guess why the series are shown together, separate charts may be clearer.

How to add a secondary axis in Excel

For a clear first result, organize the data in columns with a shared category column, such as months, and one column for each series. Select the data, then use Insert to create a chart. If you have not chosen a chart type yet, the Combo chart option is a convenient way to assign different chart types and axes in one dialog.

Select the chart. If necessary, select a series by clicking one of its bars, line points, or other plotted marks.
On the ribbon, choose Chart Design > Change Chart Type.
In the chart-type dialog, select Combo. Choose a chart type for each listed series, such as clustered column for sales and line for visits.
Check Secondary Axis on the row for the series that needs its own scale. Usually, leave the primary measure unchecked.
Select OK. Excel adds a second vertical axis, typically on the right side of the plot area.

If the chart already exists, you can also right-click the series that needs a separate scale, choose Format Data Series, and under Series Options select Secondary Axis. The wording or placement can vary slightly with chart type and Excel interface updates. If the right-click selection keeps choosing the wrong object, click the series once, then use the Format tab or the chart’s selection controls to identify the series.

On Excel for Mac, the chart-design tools and secondary-axis setting are available in the desktop app, though ribbon layout and dialog appearance can differ. Excel for the web may not expose every chart-formatting control available in the desktop version; open the workbook in the desktop app if you cannot find the Combo or axis options.

Choose chart types that make the scales understandable

For two measures tracked across the same dates or categories, columns for one series and a line for the other are often easier to interpret than two sets of columns. The line makes the secondary-axis series visually distinct, while the columns give the primary series a clear baseline. A chart with two lines can also work, provided the colors, axis labels, and legend make the mapping unmistakable.

Use the Combo dialog to set each series type rather than relying on a default chart that happens to look acceptable. A useful starting arrangement is:

Use columns for counts, sales, or other values that are naturally compared category by category.
Use a line for a rate, index, or second measure whose trend over time matters.
Keep the number of series limited. Multiple lines and multiple axes quickly make a chart hard to decode.

Some chart types, such as pie charts, do not fit the usual idea of a shared category-by-category secondary scale. If Excel will not offer the axis option for the selected chart type, switch to a compatible chart type, commonly a line, column, or combination chart. Avoid 3-D effects: perspective can make values and relationships harder to judge.

Format both axes and label the units

After adding the secondary axis, format each scale deliberately. Select the left or right axis, right-click, and choose Format Axis. In the Format Axis pane, set suitable bounds and units under Axis Options, or leave them on automatic if Excel’s choices are appropriate. You can also adjust number formatting, such as currency, percentage, or decimal places, so the scale communicates what the values represent.

Add titles for both vertical axes. With the chart selected, use Chart Design > Add Chart Element > Axis Titles, then choose the primary or secondary vertical title as needed. Give the chart a descriptive title too. A title such as Monthly revenue and orders is more informative than Sales chart, while axis titles such as Revenue ($) and Orders (count) clarify which scale belongs to which series.

Color can reinforce the connection between a series and its axis. For instance, a blue line and blue right-axis labels can help identify the corresponding measure. Do not rely on color alone: include clear axis titles, a readable legend, and adequate contrast. This matters in printouts, grayscale copies, and for readers who distinguish colors differently.

Example: revenue and order count

Imagine a worksheet with months in column A, revenue in column B, and number of orders in column C. Revenue might range from $40,000 to $90,000, while orders range from 400 to 900. Select the data and insert a combo chart. Set revenue as clustered columns on the primary axis and orders as a line on the secondary axis. Label the left axis Revenue ($) and the right axis Orders.

Both series now share the months along the horizontal axis, making it possible to see whether peaks and dips occur in the same periods. The chart does not prove that more orders caused higher revenue. Average order value, discounts, product mix, and other factors could also affect the relationship. The visual is a way to examine aligned patterns, not a substitute for analyzing the data behind them.

Check the actual axis bounds before drawing conclusions. If the revenue axis starts at $35,000 rather than zero, ordinary changes may look more dramatic than they would on a zero-based scale. That can be appropriate for showing variation, but the chart should make the bounds easy to see and should not imply that a small change is enormous. The right axis may also start above zero, so readers need to inspect both scales rather than compare the plotted heights alone.

How to decide whether two axes are misleading

Two scales can make unrelated or weakly related trends appear to move together. Because each axis can have its own minimum and maximum, a chart maker can make the series look closely aligned by adjusting those bounds. That visual alignment does not establish a statistical relationship, and it can change when the axis limits change.

Before sharing a dual-axis chart, ask these questions:

Do the two measures answer one clear question, and do they share a sensible category or time axis?
Are both axis titles, units, and scales visible without relying on the legend alone?
Would separate charts or an indexed view communicate the comparison more honestly?
Have the axis limits been chosen to show the data fairly rather than to exaggerate similarity?

When the goal is to compare direction rather than actual magnitudes, say so in the title or accompanying text. If you want to compare change from a starting point, an indexed chart can be clearer: calculate each series as a percentage of its own starting value and plot those indexed values on one axis. That changes what the chart represents, so retain or link to the original values when readers need the actual units.

Alternatives to a dual-axis chart

A secondary axis is not always the best solution. Small multiples—two separate charts with the same time axis—make each measure’s scale explicit and reduce the chance that readers confuse units. They are especially useful in reports where precise interpretation matters more than saving space.

If both measures use the same unit but differ greatly in magnitude, consider whether a logarithmic axis is appropriate. A logarithmic scale can show a broad range of positive values, but it changes how equal distances are interpreted and cannot represent zero or negative values in the ordinary way. It is not a general fix for mismatched units.

For comparing relative movement, rebasing each series to 100 at a chosen starting period can put both on one scale. For comparing the composition of a whole, a percentage chart may be more suitable. Choose based on the question: actual amount, trend, rate of change, or share of total. A chart should make that choice visible rather than conceal it.

Frequently Asked Questions

How do I put a second scale on the right side of an Excel chart?
Select the series, right-click and choose Format Data Series, then select Secondary Axis under Series Options. You can also use Chart Design > Change Chart Type > Combo and check Secondary Axis for the relevant series.

Can I use two different units in one Excel chart?
Yes. A secondary axis can display a second series in different units, such as dollars and units sold. Add titles that state each unit clearly, and explain why the measures are shown together.

Why is the secondary axis option grayed out?
The selected chart type or selected chart element may not support the option in that context. Make sure you have selected a data series, not the chart area or an axis, and try a compatible type such as a line, column, or combo chart.

Can I have more than two axes in Excel?
Standard Excel charts are designed around a primary and a secondary axis, not a series of independently scaled vertical axes. Adding more scales usually requires a different visual design or specialized workarounds, which can be difficult to read and maintain.

Should the second axis start at zero?
Not automatically. Choose bounds that suit the measure and make variation understandable, but disclose and inspect nonzero bounds because they can magnify apparent changes. For bar or column comparisons, a zero baseline is often important because bar length encodes magnitude.

Try it: the Percentage Formula Generator: percent of, percent change, increase and decrease, with the formula.

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

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