What Is a Line Chart? Examples & Best Practices

A line chart, also called a line graph or line plot, is a data visualization that uses points connected by line segments to show how a value changes across a continuous interval, most often time. Each point represents a measured value, and the connecting line helps readers quickly see trends, increases, decreases, and patterns in the data.

Line charts are one of the most common chart types because they make change easy to understand. Instead of reading rows of numbers in a table, users can look at the slope and direction of the line to understand whether a metric is rising, falling, staying stable, or fluctuating.

Why Line Charts Are Important

Line charts are especially useful for showing trends over time. Businesses, analysts, researchers, educators, and product teams use them to track metrics such as sales revenue, website traffic, stock prices, customer growth, temperature changes, and monthly expenses.

A line chart works well when the horizontal axis represents a continuous progression, such as days, weeks, months, years, or another ordered interval. The vertical axis shows the value being measured, such as revenue, users, temperature, or percentage change.

For example, a company might use a line chart to show monthly sales over a year. If the line rises from January to June, dips in July, and rises again in Q4, the viewer can immediately understand seasonal movement and overall performance.

Key Parts of a Line Chart

A clear line chart usually includes several basic elements:

• Title: Explains what the chart shows.
• X-axis: Usually displays time or another continuous sequence.
• Y-axis: Displays the measured value.
• Data points: Mark the exact values being plotted.
• Line segments: Connect the data points to reveal movement and direction.
• Labels and scale: Help readers interpret the chart accurately.

The power of a line chart comes from the relationship between the data points and the connected line. The points show individual values, while the line reveals the pattern between them.

When to Use a Line Chart

Use a line chart when your goal is to show how a numeric value changes over a continuous or ordered variable. This makes line charts ideal for time series data, where observations are recorded at regular intervals such as hourly, daily, weekly, monthly, or yearly.

Good use cases include:

• Tracking monthly revenue
• Monitoring website visits over time
• Comparing product signups by week
• Showing temperature changes during a day
• Measuring stock price movement
• Analyzing customer churn trends
• Comparing campaign performance across several months

Line charts are less effective when your data is purely categorical and has no meaningful order. For example, if you want to compare sales by product category, a bar chart may be clearer than a line chart.

Common Types of Line Charts

Simple Line Chart

A simple line chart uses one line to show the movement of a single metric. For example, a business might use one line to show total monthly revenue.

Multiple Line Chart

A multiple line chart uses two or more lines to compare related data series. For example, a SaaS company might compare monthly signups for three pricing plans on the same chart. Multiple lines are useful, but too many lines can make the chart hard to read.

Stacked or Compound Line Chart

A compound line chart shows how multiple values contribute to a total. This can be useful for showing how different segments change over time, although stacked area charts are often clearer for part-to-whole relationships.

Line Chart Example

Imagine a website tracks monthly organic traffic:

Month	Organic Visits
January	12,000
February	14,500
March	18,000
April	17,200
May	21,000
June	25,500

A line chart would place the months on the x-axis and organic visits on the y-axis. The line would show traffic increasing from January to March, dipping slightly in April, and then rising again through June. This visual pattern is easier to understand than the table alone.

Best Practices for Creating Line Charts

To create a line chart that is accurate and easy to read, follow these best practices:

1. Use line charts for continuous or ordered data. Line charts work best when the x-axis has a meaningful order, especially time.

2. Keep the chart simple. Avoid adding too many lines. If the chart becomes crowded, split the data into smaller charts or highlight only the most important series.

3. Use clear axis labels. Readers should immediately know what each axis represents and what unit is being measured.

4. Choose an appropriate scale. A misleading y-axis scale can exaggerate or hide changes. Make sure the scale supports honest interpretation.

5. Show data points when helpful. If the chart has only a few observations, visible markers can help users see exact values.

6. Use color carefully. In multiple line charts, each line should be visually distinct. Avoid using colors that are too similar.

7. Add context. Labels, annotations, or brief notes can explain sudden spikes, drops, or important events.

Line Chart vs. Bar Chart

A line chart is best for showing change over time, while a bar chart is often better for comparing separate categories. For example, use a line chart to show monthly revenue growth, but use a bar chart to compare revenue by region.

If the order of the x-axis matters, a line chart may be the right choice. If the categories are independent, a bar chart is usually easier to understand.

Advantages of Line Charts

Line charts offer several advantages:

• They make trends easy to spot.
• They work well for time-based data.
• They can compare multiple data series.
• They show increases, decreases, and fluctuations clearly.
• They are familiar to most readers.

Because line charts are simple and widely recognized, they are useful for dashboards, reports, presentations, and analytics tools.

Limitations of Line Charts

Line charts also have limitations. They can become confusing when too many lines are added. They may also imply continuity between points, which can be misleading if the data is not truly continuous. For categorical comparisons, other chart types such as bar charts or dot plots may be more appropriate.

Conclusion

A line chart is one of the most effective ways to visualize trends, patterns, and changes over time. By connecting data points with line segments, it turns raw numbers into a visual story that is easier to read and interpret.

Use a line chart when you need to track continuous data, compare trends, or understand how a metric changes across time. With clear labels, a sensible scale, and a focused message, a line chart can make complex data simple, useful, and actionable.

FAQ

What is a line chart used for?

A line chart is used to show how a value changes over time or across another continuous interval. It is commonly used for trend analysis, business reporting, finance, science, and performance tracking.

What is the difference between a line chart and a line graph?

There is usually no practical difference. "Line chart" and "line graph" are commonly used to describe the same visualization: data points connected by line segments.

When should you not use a line chart?

Avoid using a line chart when your data categories are unrelated or unordered. In those cases, a bar chart is often clearer.

Can a line chart show multiple data series?

Yes. A multiple line chart can compare two or more metrics over the same interval, such as revenue from different products over several months.

Further reading

• Free line chart maker — templates, editor, and export walkthrough
• Line chart templates — browse ready-made layouts
• Line charts in BeCharts documentation