What is a Data Series in Excel?

A data series is the fundamental building block of any chart in Excel. Understanding how to manage it is the key to turning your spreadsheets into clear, insightful visuals. This guide will walk you through exactly what a data series is, how Excel uses it, and how you can customize it to build more effective charts and reports.

What is a Data Series?

In the simplest terms, a data series is a collection of related data points plotted on a chart. These points come directly from the rows or columns in your spreadsheet. Think of a single column of monthly sales figures or a row of quarterly profit numbers - that's a data series. When you create a chart, you're essentially telling Excel to visualize one or more of these series.

Let's break it down with a simple example. Imagine you're a small business owner tracking website traffic over the first four months of the year. Your data might look like this:

In this scenario:

• The data series is the set of numbers in the "Website Visits" column: {1500, 1750, 2100, 2000}. These are the values that will be plotted on your chart.
• The series name is "Website Visits." Excel automatically pulls this from the column header.
• The category labels are the values in the "Month" column: {"Jan", "Feb", "Mar", "Apr"}. These labels will appear on the horizontal axis (X-axis) to give context to each data point.

When you turn this data into a line chart, Excel plots each "Website Visit" value as a point and connects them, giving you a clear visual trend of your traffic growth.

Creating a Chart from a Data Series

Creating a basic chart in Excel is straightforward. First, select the entire data range, including the headers (in our example, an A1:B5 selection). Then, go to the Insert tab on the Excel ribbon and choose a chart type from the Charts group, like a Clustered Column or a Line chart.

Excel will instantly generate a chart. It intelligently identifies that "Website Visits" is the data series you want to plot and that "Month" contains the labels for the horizontal axis. This automatic detection works well for simple, clearly labeled data tables.

Working with Multiple Data Series

The real power of charting comes from comparing different sets of data. You can do this by adding multiple data series to a single chart. This is perfect for comparing performance across different time periods, products, or marketing channels.

Let's expand our website traffic example to compare this year's performance against last year's. Our new table looks like this:

Now we have two data series:

• "2023 Visits": The data from the second column.
• "2024 Visits": The data from the third column.

When you select this entire table and create a line chart, Excel automatically plots both columns as separate lines, each with a different color. It also creates a legend to help you distinguish between "2023 Visits" and "2024 Visits." Immediately, you can see how 2024 traffic is trending compared to the previous year.

Customizing Your Data Series for Maximum Impact

Excel's default charts are functional, but a little customization can make your data much easier to read and understand. You can format each data series independently to emphasize key information.

To start customizing, right-click directly on the data series you want to change (for example, click on one of the lines or columns in your chart) and select Format Data Series.... This will open a formatting pane on the right side of your screen with several powerful options.

Fill & Line

This is where you control the appearance of your data series. The options will change depending on your chart type.

• For Column or Bar Charts: You can change the fill color of the bars. A great tip is to use your brand's colors or choose colors that have clear emotional associations (e.g., green for positive growth, red for a decline). You can also adjust the border (line) of each column.
• For Line Charts: You can change the line color, style (solid, dashed, dotted), and thickness. You can also customize the markers - the dots that represent each data point - by changing their shape, size, and color. Making markers more prominent can help draw attention to specific data points.

Series Options

This tab contains more advanced structural adjustments for your data series.

• Plot Series on Secondary Axis: This is an incredibly useful feature when you want to plot two data series that have very different scales. For example, imagine you want to show Website Visits (in thousands) and Conversion Rate (as a percentage) on the same chart. If you plot them on the same axis, the percentage values will look like a flat line at the bottom. By moving the Conversion Rate series to a "Secondary Axis," you create a second vertical axis on the right side of the chart scaled specifically for that data. To do this, right-click the series you want to move, open Format Data Series, and under Series Options, select Secondary Axis.
• Gap Width (for Column/Bar Charts): This slider lets you control the amount of empty space between your columns. Reducing the gap width can make the columns look more substantial, while increasing it can create a lighter, more spacious feel.

Editing and Managing Your Data Series

What if you need to add new data to your chart or change the source of an existing series? You don't have to start from scratch. Excel's Select Data Source manager gives you full control over what's being plotted.

To open this menu, right-click anywhere on your chart and choose Select Data...

This dialog box has two main sections:

1. Legend Entries (Series): This list on the left shows all the data series currently in your chart. From here, you can:
2. Horizontal (Category) Axis Labels: This box on the right controls the labels on your X-axis. If they are incorrect, click the "Edit" button and select the correct range of cells (e.g., the column containing the month names).

The Switch Row/Column button is also a lifesaver. Sometimes, Excel incorrectly guesses how your data is structured. If it plots your categories as a data series and your data series as categories, clicking this button often fixes it with a single click.

Common Data Series Challenges and Solutions

Even experienced Excel users run into charting hiccups. Here are a few common issues and how to resolve them.

1. My chart has empty spaces for blank cells.

If your data range contains empty cells, Excel will, by default, show them as gaps in your chart. Sometimes this is what you want, but other times you might prefer the chart to treat them as zeros or to connect the line over the gap.

Solution: In the Select Data Source window, click the Hidden and Empty Cells button in the bottom-left corner. You will get a small pop-up with options to display empty cells as "Gaps," "Zero," or "Connect data points with line." Choose the one that best represents your data.

2. Excel is plotting my dates or labels as a number series.

This often happens when your category labels (like years or IDs) are numbers. Excel might mistake it for another data series and plot it as a line or set of columns.

Solution: Open the Select Data Source window. Check the list of "Legend Entries (Series)." You will likely see your number-based labels listed there. Select it and click Remove. Next, make sure the correct range is selected under "Horizontal (Category) Axis Labels."

3. My new data isn't showing up on the chart.

If you add new rows of data to your table, they may not automatically appear in your chart. This is because the chart's data series is still linked to the original cell range.

Solution: There are two easy ways to fix this.

• Drag to Expand: Click on your chart, and you'll see a colored outline around the data source in your spreadsheet. You can drag the corner of this outline to include your new rows or columns.
• Edit the Series: Right-click the chart, choose Select Data, click on the series you want to update, click Edit, and re-select the entire "Series values" range to include the new data.

Final Thoughts

At its core, a data series is simply the set of values from your spreadsheet that powers your chart. By understanding how to create, manipulate, and format these series, you unlock the ability to transform confusing rows of numbers into clean stories that drive better decisions.

While mastering data series in Excel is a valuable skill, keeping multiple reports and dashboards updated across different data sources can still be a time-consuming manual process. At Graphed, we’ve automated this entire workflow. By connecting your tools like Google Analytics, Shopify, or Salesforce directly to our platform, you can use simple, natural language to instantly build the live dashboards you need. It’s like having a data analyst on your team who works in seconds instead of hours, giving you back time to focus on strategy instead of report-building.