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To add a trendline in Google Sheets, double-click the chart, open Customize then Series, and click Trendline. Google documents trendlines for bar, line, column and scatter charts only, so the most common reason the option is missing is the chart type. The steps below follow Google’s help page, and the sections after them cover what each trendline type is for and how to read the R squared label.
What a trendline is used for in research
A trendline is a line drawn through a chart’s data series to show its overall direction. Google’s chart guide recommends a line chart to look at trends or data over a time period, and a scatter chart to show numeric coordinates along the horizontal (X) and vertical (Y) axes and look for trends and patterns between two variables. A trendline is most often added to a scatter chart of two measured variables, or to a line chart of a measurement over time.
A fitted line summarises a pattern; it does not show that one variable causes the other. See spurious correlation and the correlation coefficient guide before describing a trendline as evidence of a relationship in a report or manuscript.
Access: where trendlines live in Google Sheets
Trendlines are a built-in part of the chart editor in Google Sheets, on the Series settings under Customize. Google’s help page for the feature describes the steps for Google Sheets on a computer, and the steps below are the ones it gives for a computer.
How to add a trendline in Google Sheets, step by step
- Open the spreadsheet in Google Sheets and make sure the data is already plotted in a chart. If it is not, see how to make a histogram on Google Sheets for an example of working in the chart editor.
- Double-click the chart. The chart editor opens on the right.
- On the right, click Customize, then Series.
- Optional: next to Apply to, choose the data series you want the trendline for.
- Click Trendline.
If the Trendline option does not appear, Google’s help page states that trendlines do not work with your data.
How to add trendlines to a chart with several series
The Apply to setting in step 4 chooses the data series the trendline applies to.
How to add a trendline to a scatter chart
The steps are the same as above: scatter charts are one of the four chart types Google lists as supporting trendlines, alongside bar, line and column charts.
Choose a trendline type
After you click Trendline, the same Series settings let you change the trendline type. Google describes the types as follows.
| Type | When Google says it fits |
|---|---|
| Linear | Data that closely follows a straight line |
| Exponential | Data that rises or falls in proportion to its current value |
| Polynomial | Data that varies; a polynomial degree setting appears for this type only |
| Logarithmic | Data that rises or falls quickly and then levels off |
| Power series | Data that rises or falls at a constant rate relative to its current value |
| Moving average | Smooths data that is unstable or highly variable; average type and periods settings appear for this type only |
Edit the trendline and read the output
Under Trendline in the Series settings you can change the trendline type, the line color, opacity and thickness, and the label. Two further settings only exist for particular types: the polynomial degree for polynomial trendlines, and the average type and periods for moving averages.
R squared
The R squared option shows how closely the trendline fits the data. Google states that the closer the value is to 1, the closer the fit. The R squared label is only available if you add a legend to the chart, so turn the legend on first if the option does not show. For how to interpret the value in a research report, including what it does not tell you, see how to interpret R squared.
Troubleshooting
The Trendline option is missing
Check the chart type first. Google lists bar, line, column and scatter charts as the types that support trendlines; other chart types and some data sets do not. If the chart type is supported and the option is still missing, Google’s help page says trendlines do not work with that data.
The R squared label does not appear
Add a legend to the chart. Google states the R squared label is only available with a legend.
The polynomial degree or moving average settings are not visible
These settings are shown only for their own trendline type. Change the type to polynomial or moving average to see them.
Alternatives to a chart trendline
A chart trendline is a visual fit. If you need the fitted slope as a number to report, the CASRAI guide how to find a slope in Excel covers that task in Excel, and how to make a scatter plot in Excel covers the matching chart. The guide to a linear regression scatter plot explains what the fitted line represents.
FAQ
How do I add a trendline in Google Sheets?
Double-click the chart, choose Customize, then Series, optionally pick the data series under Apply to, and click Trendline.
Which charts support a trendline in Google Sheets?
Bar, line, column and scatter charts, according to Google’s help page. Other chart types do not support trendlines.
Why can I not see the trendline option?
Either the chart type is not one that supports trendlines, or Google’s trendline feature does not work with that data set.
How do I show R squared on a trendline?
Turn on the R squared setting under Trendline in the Series settings. It only appears if the chart has a legend.
Can I change the trendline from linear to another type?
Yes. The Series settings let you choose linear, exponential, polynomial, logarithmic, power series or moving average.
Sources
- Google Docs Editors Help, Add and edit a trendline, checked 2026-10-29.
- Google Docs Editors Help, Types of charts and graphs in Google Sheets, checked 2026-10-29.
