How to add a trendline to a chart in Excel on Mac: steps for Microsoft 365

Check your chart type and Excel version first

Trendlines do not work on every chart. Microsoft says they work only on unstacked 2-D area, bar, column, line, stock, XY scatter, and bubble charts. Stacked charts are not supported. Pie charts are not on that list either, so change the chart type before you look for the option.

Check your Excel build too. Microsoft's release notes for Office for Mac list Excel 16.114.3 (Build 26102720) from October 27, 2026 as the latest entry. The entries before it are 16.114.2 from October 26, 2026, and 16.114.1 from October 22, 2026. Each one lists only quality and performance improvements. Microsoft's trendline steps cover Excel for Mac in Microsoft 365, Excel 2024, and Excel 2021, so any of those versions works.

To check yours, open Excel > About Excel. Write down the version number if you need help from Microsoft support. It saves a round trip when someone asks which build you run.

Add a linear trendline on a Mac chart

The most common trendline is linear. It draws a straight line through the general direction of your points, and most people try it first. The steps below use Linear as the example. The same menu works for the other types, so once you know the path, switching types takes seconds.

Which trendline type fits your data?

Pick the type that matches the shape of your data. Do not pick the one that looks smoothest. Excel draws whatever you ask for, even when the fit is poor, so the type is your call.

Linear suits steady growth or decline. Exponential suits values that grow or shrink by the same percentage over each period. Logarithmic suits data that rises quickly and then levels off. Polynomial suits curves with bends or waves. Power suits data where one value scales as a power of another. Moving average does not fit a curve at all. It smooths noise by averaging neighboring points.

A quick test helps. Look at the line against the dots. If the points sit close to the line with no clear pattern in the gaps, the type probably fits. If they bow away in one direction, try a different type and compare.

Format the trendline and show the equation

Double-click the trendline to open the Format Trendline pane. Under Trendline Options, you can turn on Display Equation on chart and Display R-squared value on chart. R-squared tells you how closely the line follows the points. A higher value means a tighter fit.

Be careful with where these switches live. Microsoft's trendline article describes a pane with name and forecast options only. The equation and R-squared switches come from The Bricks, a third-party Mac guide published April 22, 2025, which does not name an Excel version. If you do not see them, check the Format Trendline pane in your build before you assume they are missing.

In the same pane, Fill & Line controls the color, width, and dash type. A thinner, dashed line helps a trendline stand apart from a data series that already uses a bold line. That matters on a chart with several series.

Forecast ahead or backward with a trendline

Forecasting extends the fitted line into periods you have not charted yet. Open More Trendline Options, then enter a number in Forecast Forward or Backward. The number counts periods, so match it to the units on your horizontal axis. If your axis shows months, enter months. If it shows years, enter years.

A forecast only extends the line. It does not know about seasonal swings, price changes, or one-off events. Treat the extended line as a rough guide, and say so when you share the chart with someone else.

How to remove a trendline in Excel on Mac

Click the trendline to select it, then press Delete. You can also go to Chart Design > Add Chart Element > Trendline > None, which turns off the trendline for the series you selected. Deleting a trendline does not change your data. It only removes the line from the chart.

Why the Trendline option is greyed out

A grey Trendline option usually has one of a few causes. Work through them in order, starting with the chart type, because that is the most common reason.

• The chart is stacked. Microsoft says stacked charts are not supported. Go to Chart Design > Change Chart Type and pick an unstacked type.
• The chart is a type Microsoft does not list, such as a pie chart. Change the chart type first, then try again.
• You selected the wrong element. Click the series itself, not the title, an axis, or empty space, then open the menu again.
• You are working in Excel for the web. A Microsoft Q&A reply says some features are unavailable there and suggests Editing > Open in Desktop App.

Chart Design tab missing on Mac

Every trendline step starts from the Chart Design tab. If that tab does not appear when the chart is selected, it may have been dropped from the ribbon. A 2022 moderator reply in a Microsoft Q&A thread gives a fix that uses Preferences. Work through it in this order.

1. Choose Excel > Preferences.
2. Click Ribbons & Toolbar.
3. Under Choose commands from, select Tool Tabs.
4. Select Chart Design in the list.
5. Click the add arrow to move it onto the ribbon.

Then select your chart again and look at the ribbon. If the tab still does not show, check your build with Excel > About Excel and compare it with Microsoft's release notes. Then update Excel and try once more.

Mistakes people make with trendlines on Mac

• Adding the trendline to the wrong series. Check which series you clicked before you trust the line.
• Treating the equation as an exact rule. The equation describes the fitted line, not a law that will hold for future values.
• Using a stacked chart. The option will be missing or grey, so change the chart type first.
• Forecasting too far ahead. Long forecasts stretch small errors into large ones.
• Choosing a complex type because it hugs the points best. A polynomial can chase noise and predict nonsense.

Ask Lazur where the trendline button is

Hold ⌥ ⌘ (Option and Command) and ask. Lazur sees your screen while you hold the shortcut, so you can ask where a button is. Ask where Add Chart Element is, and Lazur draws a circle and a label around it. Ask how to add a trendline, and Lazur guides you one click at a time, waiting for each click before it moves on.

Lazur does not click for you, and it does not edit your chart. It points, explains, and answers out loud. You stay in control of every change in Excel, and you decide when to move to the next step.

Where to go next with your chart data

Trendlines work best on clean data. If your numbers come from raw rows, build a summary first. The pivot table guide walks through that for Microsoft 365 users. Once the chart looks right, the Excel page explains how Lazur helps with buttons and formulas on Mac.

Lazur has a 3-day Pro trial with no credit card. The trial starts when you first open the app. Prices are on the pricing page, and you can get the app from the download page.