What Are Line Charts Best Used for in Tableau?

A line chart is one of the most fundamental yet powerful tools in your data visualization toolkit, and Tableau makes creating them simple. But knowing when to use one is just as important as knowing how to build it. This guide will walk you through the best use cases for line charts in Tableau, from uncovering sales trends to comparing marketing channel performance over time.

What a Line Chart Shows (and Why It Matters)

Before jumping into specifics, let's quickly recap what a line chart does. It connects a series of data points with a continuous line to display information. The horizontal axis (x-axis) almost always represents an interval of time - hours, days, months, or years. The vertical axis (y-axis) represents a quantitative value or metric you want to measure.

This structure makes line charts unbeatable for one primary job: showing change over a continuous period of time.

Your brain is wired to interpret the shape of a line. An upward slope means growth. A downward slope means decline. Peaks and valleys instantly tell you about highs and lows. This intuitive understanding is what makes line charts so effective for telling stories with your data.

Best Use Cases for Tableau Line Charts

1. Tracking Performance and Trends Over Time

This is the classic, number-one reason to use a line chart. Whenever you have a question that starts with "How did [metric] change over [time period]?" a line chart is your answer.

It visually represents the journey of a single metric, making it easy to spot trends, accelerations, or decelerations that you’d miss in a table of numbers. Think of it as the timeline of your data.

Common examples include:

• Tracking monthly website traffic from Google Analytics
• Visualizing quarterly sales figures to see growth patterns
• Monitoring daily new customer sign-ups from your CRM
• Showing fluctuations in stock prices over a year

Getting Started in Tableau:

Creating a basic line chart is straightforward. Place your time-based dimension (like an order date) on the Columns shelf and your measure (like Sales) on the Rows shelf. Tableau will often default to a line chart for you when it recognizes a date dimension.

2. Comparing Multiple Categories Over the Same Time Period

Line charts aren't just for single metrics. They become even more insightful when you overlay multiple lines to compare different categories. This allows you to see not just what happened, but also to compare the performance of different segments side-by-side.

This is perfect for answering questions like, "Which of our marketing channels is growing the fastest?" or "How do sales in North America compare to sales in Europe this year?"

Practical applications:

• Marketing: Plotting traffic from different sources (Organic, Social, Paid Search) to see which channels are driving growth
• Sales: Comparing the monthly sales performance of different product categories or sales teams
• Operations: Tracking the daily production output of several different manufacturing plants

How to do it in Tableau:

After creating your basic line chart, simply drag a dimension that represents your categories (e.g., 'Product Category' or 'Marketing Channel') onto the Color button on the Marks card. Tableau will instantly create a separate, color-coded line for each member of that dimension, along with a helpful legend.

3. Identifying Seasonality and Cyclical Patterns

Does your revenue always dip in the summer? Do website visits spike every weekend? Line charts are fantastic for revealing these kinds of seasonal or cyclical patterns in your data.

When you look at data over a long enough time span (like several years), these repeating patterns become obvious. A flat table of sales data for the last 36 months would make it difficult to spot that every December sees a huge spike. On a line chart, that peak would be impossible to miss.

Tips for spotting patterns in Tableau:

Make sure your date field is set to a continuous value (it will be green in the Columns shelf) to get a single, unbroken timeline. You can right-click the date pill to change its granularity from Year to Quarter, Month, or even Day. Looking at your data at different levels of detail can reveal patterns you wouldn't otherwise notice.

Powerful Tableau Line Chart Variations

Once you’ve mastered the basics, you can use some of Tableau's advanced features to create even more compelling visualizations.

Dual-Axis Charts: Telling a Richer Story

Sometimes you need to compare two different metrics that have vastly different scales. For example, what if you want to see if your marketing spend impacts website sessions? You couldn't plot 'Ad Spend' (in thousands of dollars) and 'Sessions' (in millions) on the same axis, one line would look completely flat.

A dual-axis chart solves this. It allows you to have two different y-axes, one on the left and one on the right, scaled independently. This lets you plot a line chart for 'Ad Spend' against a bar chart or another line chart for 'Sessions' to see if there's a correlation between them.

Steps for a dual-axis chart in Tableau:

1. Place your two measures on the Rows shelf (e.g., SUM(Ad Spend) and SUM(Sessions))
2. Right-click the second pill on the Rows shelf and select "Dual Axis."
3. Tableau will create two axes. Be sure to right-click on one of the axes and select "Synchronize Axis" if you want the grids to align. You can change the Marks type for each measure independently to have, for instance, bars for one and a line for the other.

Area Charts: Emphasizing Volume and Magnitude

An area chart is simply a line chart with the area below the line filled in. Filling the area with color helps emphasize the magnitude of the values and the total volume over time. These are great for showing cumulative totals or how a part-to-whole relationship has changed over a period.

For example, a stacked area chart could show how your total revenue is composed of revenue from different product lines each month. You can see both the change in the total revenue (the top of the overall shape) and the contribution of each component.

Just a word of caution: Stacked area charts can be misleading if you have too many categories, as it can be hard to interpret the trends of the inner segments. Stick to a few categories for clarity.

Best Practices for Clear and Effective Line Charts

A great line chart isn't just accurate, it's also easy to read and understand. Here are a few tips to follow in Tableau:

• Limit the Number of Lines: Too many lines create what’s often called a "spaghetti chart" — a tangled mess that’s impossible to read. A good rule of thumb is to use no more than four or five lines on a single chart. If you need more, consider breaking the chart into smaller multiples.
• Use Color Thoughtfully: Use distinct, easily distinguishable colors for each line. Pay attention to accessibility by using colorblind-friendly palettes. Tableau has some excellent built-in options.
• Clear Labeling is Key: Always give your chart a descriptive title. Label your x-axis and y-axis clearly so there’s no ambiguity about what the reader is looking at. Include a legend if you have multiple lines.
• Start the Y-Axis at Zero (Usually): To provide an accurate sense of scale and change, the y-axis for a line chart should generally start at zero. Truncating the axis can exaggerate changes and mislead the viewer. The main exception is for data like stock prices or temperature, where you're focused on fluctuations within a narrow band of high values.
• Don't Forget Markers: Adding markers (dots, squares, etc.) to your data points can make the chart easier to read, especially if the line is faint or you want to highlight specific points in time. You can adjust this on the Marks card in Tableau.

Final Thoughts

In short, line charts are your go-to visualization for anything related to time. They excel at showcasing trends, comparing different groups, and spotting cyclical patterns, giving you a clear storyline of how your key metrics perform from one point in time to another.

At Graphed, we think getting these kinds of powerful insights shouldn't require you to become an expert in a complex BI tool. Instead of clicking and dragging to build your charts, we enable you to simply ask for what you want in plain English. For example, you could ask, "Show me a line chart of Shopify revenue vs Facebook Ads spend this quarter," and our AI data analyst builds a live, interactive dashboard for you in seconds, automatically connecting to your live data so it's always up-to-date.