Posted on April 25, 2022 (Updated on July 27, 2025)

How do you overlay two graphs in Excel with different Y axis?

Space & Navigation

Excel Charts: When One Y-Axis Just Isn’t Enough (and How to Fix It!)

Excel’s great for turning raw data into something visual, but let’s be honest, sometimes a single chart just doesn’t cut it. Ever tried cramming wildly different numbers onto the same graph? It’s a mess! That’s where overlaying graphs with different Y-axes comes to the rescue. Think of it as giving each set of data its own stage to shine on, all within the same picture. This article will walk you through creating these charts, explaining why they’re so useful, and even pointing out a few potential pitfalls to avoid.

Why Bother with a Second Y-Axis?

A secondary axis is your secret weapon when you need to compare apples and oranges – or, more accurately, sales figures and profit margins. Imagine trying to plot both on the same scale. Your profit margin, usually a small percentage, would look like a flat line hugging the bottom. Useless! A secondary axis gives that profit margin its own scale, letting you actually see how it fluctuates alongside your sales.

Think about it this way:

  • Sales vs. Profit Margin: As mentioned, a classic example. You want to see if higher sales actually lead to higher profits, right?
  • GDP and Growth: Plotting the actual GDP alongside its growth rate on the same chart? Forget about it without a second axis.
  • Temperature and Rainfall: Trying to understand how rainfall affects temperature? You’re dealing with completely different units. A secondary Y-axis is a must.

Basically, if you’re trying to compare data sets that are measured differently or have vastly different ranges, a secondary Y-axis is your friend. It lets you tell a richer, more nuanced story with your data.

Let’s Build an Overlay Chart: A Step-by-Step Guide

Ready to dive in? Here’s how to create an overlay chart with different Y-axes in Excel:

  • Get Your Data Ready: Think of it like prepping your ingredients before you start cooking. Organize your data into columns. Your first column is the common thread – maybe dates or time periods. The other columns? Those are your Y-axis values for each data series.
  • Insert a Chart: Highlight all your data, including those column headers. Head over to the “Insert” tab and pick a chart. A “Combo” chart (look for “Clustered Column – Line on Secondary Axis”) is usually the best starting point. Pro-tip: if you’re on a newer version of Excel (2013 or later), the “Recommended Charts” feature can be a lifesaver.
  • Tweak the Chart Type (If Needed): If Excel didn’t guess right, no worries! Just select your chart, and you’ll see the “Chart Tools” tabs pop up. Go to “Chart Design” and hit “Change Chart Type.” Then, choose “Combo.”
  • Assign Those Axes!: This is where the magic happens. In the “Combo” chart settings, you get to decide which data series goes on which axis. You also get to pick the chart type for each one (column, line, etc.). Just check the “Secondary Axis” box for the series you want on the right-hand side.
  • Scale It Right: Excel’s pretty smart, but sometimes it needs a little help. Right-click on the axis you want to adjust and select “Format Axis.” Now you can play with the minimums, maximums, and intervals to make sure your data looks its best.
  • Add the Finishing Touches: Don’t forget the labels! Axis titles, a chart title, and a legend are crucial. And use different colors for your data series – it makes a huge difference in readability.

    • Example Time: Sales and Profit Margin in Action

    Let’s say you’ve got this data:

    MonthSales ($)Profit Margin (%)January100,0002%February120,0003%March110,0002.5%April130,0003.5%

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