Google Sheets Chart With Two Y-Axes: Setup and Tips

Yes. In Google Sheets, you can put one data series on a second, right-side y-axis: open the chart editor, go to Customize > Series, choose the series, then set Axis to Right axis. A combo chart is often a useful starting point when the series have different units or very different scales.

What two y-axes mean

A chart with two y-axes has a vertical scale on the left and another on the right. Each scale can represent a different data series. The horizontal axis is usually shared, so both series are plotted against the same dates, categories, or other x-axis values.

For example, a monthly report might show revenue in dollars and website visits in thousands. Revenue could use the left axis, while visits use the right. If both series were forced onto a single scale, the smaller-valued series might appear nearly flat, even when it changes substantially over time.

In Sheets, a series assigned to the right axis is not converted or recalculated. Its values stay the same; the chart simply draws them against the scale shown on the right. The second axis is sometimes called a secondary axis. It is not a second horizontal axis, and it does not create a new data table.

When a second axis is useful

A second scale can make a chart more readable when two related series use different units, such as temperature and rainfall, or when one series has values much larger than another. It can also help compare the timing of changes: for example, whether sales and advertising spend tend to rise in the same months.

Use one only when the comparison has a clear purpose. Two axes can make visual relationships look stronger or weaker depending on how each scale is set. A line for one measure may appear to track another closely even when their values do not share a meaningful scale. Readers should be able to tell which series belongs to which axis and what each axis measures.

Prepare the data before inserting a chart

Arrange the information in a simple table, with one column for the shared x-axis labels and a separate column for each series. A monthly table might have Month, Revenue, and Visits as its three headers, followed by one row per month. Keep the labels consistent and avoid blank rows inside the range.

Use descriptive column headings that include units when that helps, such as Revenue (USD) and Visits (thousands). Clear headers make it easier to identify a series in the chart editor and make the finished chart easier to interpret. If the visit figures are actual counts, do not label them as thousands unless the values have been scaled accordingly.

Select the full table, including the headers. If the chart is already created, you can change its data range in the chart editor rather than starting over. Check that the first column is being used as the x-axis and that each numeric column appears as a separate series.

Create a chart in Google Sheets

Select the data range, including its header row.
Choose Insert > Chart. Sheets inserts a chart and opens the Chart editor, usually on the right side of the browser window.
In the editor’s Setup tab, check the data range, x-axis, and series. Turn on the options to use the first row as headers and the first column as labels if Sheets has not recognized them correctly.
For a flexible chart with different visual forms for the series, choose Combo chart from the Chart type menu. You can also try another chart type if it offers the series-axis setting you need.
Open Customize > Series to assign a series to the right axis.

The chart editor is part of Google Sheets in a web browser. Its available choices can depend on the selected chart type and the data structure. If you cannot find an axis setting, first check that the chart has multiple numeric series and try a combo chart.

Assign a series to the right axis

In Customize > Series, use the series selector, often labeled Apply to, to choose the data series you want to move. Then open the Axis menu and choose Right axis. The selected series should now be plotted against the scale on the chart’s right side. Leave the other series on the left axis unless you have a specific reason to move it.

To change the appearance of the series, use the series selector and the available formatting controls in the same section. For a combo chart, you can choose a visual type for a series, such as a line or column, where Sheets provides that option. A common design is columns for volume and a line for a rate or percentage, but the best choice depends on what the data represents.

To adjust the scale or labels, look under Customize for the vertical-axis settings. The left and right axes may have separate controls; check the axis selection before changing titles, number formats, or bounds. Give each axis a descriptive title, and format values as the correct kind of measure, such as currency, percent, or whole-number counts.

A concrete example: revenue and visits

Suppose a table contains monthly revenue from $8,000 to $15,000 and website visits from 20,000 to 45,000. The numbers have different meanings and ranges. In a combo chart, you could display revenue as columns on the left axis and visits as a line on the right. Label the axes Revenue (USD) and Website visits, and make the legend names equally clear.

This layout can show whether the two measures tend to change during the same months. It does not prove that visits caused revenue to change, or that the relationship is statistically meaningful. Seasonal effects, promotions, pricing, or other factors might affect either series. The chart is a visual summary, not an explanation of cause.

If the purpose is to compare percentage change rather than actual values, consider converting both series to a common index or percentage-change basis in the source data. That can make the comparison more direct, but it changes what the chart communicates. Label the transformation and retain the original figures elsewhere if readers need the actual amounts.

Make the two scales easy to read

Two vertical scales add information, but also add visual work for the reader. Use color consistently: a series and its axis title or tick labels can share a color when the chart’s formatting options allow it. Keep the legend, line styles, and column colors distinct enough to identify each measure without relying on color alone.

Title the chart with the subject and time period, rather than using a generic title such as Chart title.
Label both y-axes with the measure and unit. A right-side scale without a clear label is easy to misread.
Choose readable number formats and avoid unnecessary decimal places.
Keep the same dates or categories aligned for both series, and use a legend that matches the headers.
Review the chart at its intended display size; axis titles and labels can become crowded in a narrow chart.

Be cautious about manually setting minimum and maximum bounds. Tight bounds can make ordinary variation look dramatic, while very broad bounds can hide useful differences. If you set bounds to focus attention on a range, make that choice clear to readers.

Limits and common interpretation problems

The most important limitation is that the two axes have independent scales. Their visual slopes and crossings are not directly comparable in the way they would be if both series shared one scale. Changing either axis range can change the apparent alignment of the lines without changing any underlying values. Avoid using the visual intersection of two lines as evidence that the measures are equal or have a special relationship.

A dual-axis chart is also a poor fit when the series do not share a meaningful x-axis, when there are too many series to distinguish, or when readers need precise comparisons between values. In those cases, separate charts with clearly labeled scales may be easier to understand. If exact comparisons matter, a table alongside the chart can provide the underlying values.

Another common mistake is plotting a percentage and a count without labeling the units. Even if the two series move together, their scales and meanings differ. Explain the measures in the axis titles or a nearby note; do not expect color alone to communicate the distinction.

Alternatives to a chart with two axes

A dual-axis combo chart is not the only way to show related data. Separate small charts can preserve a consistent scale for each measure and reduce the risk of readers confusing the axes. This works well in a dashboard when there is room to place the charts together and align their time periods.

Another option is to transform the data to a shared basis, such as an index where both series start at 100, or to show percentage changes. This emphasizes relative movement rather than original units, so it should not replace actual-value reporting when amounts matter. A table is often the clearest choice for a small number of categories or when exact values matter more than the overall pattern.

In Microsoft Excel, the general idea is similar: a secondary vertical axis can be assigned through chart formatting, and combo charts are commonly used. The menus and editor differ, however, so the Google Sheets paths above should not be followed in Excel.

Frequently Asked Questions

Can Google Sheets have two y-axes?
Yes. In the web version of Sheets, select a series in Customize > Series and set its axis to Right axis. The chart type must support the setting; a combo chart is a practical option to try.

How do I add a secondary axis in Google Sheets?
Create or select a chart, open the Chart editor, and go to Customize > Series. Choose the intended series in the selector, then choose Right axis in the Axis menu.

Can I put one series on the left and one on the right?
Yes. Keep one series on the left axis and assign the other to the right. The two series can use different units, but each axis should be clearly labeled so readers know which scale applies.

Why can’t I see the right-axis option?
Check that the chart includes more than one numeric series and that you have selected a series rather than the chart title or another element. Some chart types do not expose the same series controls. Try changing the chart type to a combo chart and look again under Customize > Series.

Should I use two y-axes or two separate charts?
Use two axes when the series share a useful x-axis and a combined view helps readers understand their timing. Use separate charts when the scales could mislead, the measures are hard to distinguish, or precise comparisons matter more than a compact display.

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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