Grouped Line Chart
A grouped line chart, also called a multi-line chart, displays multiple lines on the same chart - one per category in a breakdown dimension. Each line traces how its category’s value evolves over time, making it easy to compare trends side by side.
Grouped line charts excel at showcasing trends over time for multiple items in a category.
This multi-line chart uses colors to highlight different trends
Creating an Effective Grouped Line Chart
Recommended data types for each axis:
- X-Axis Dates or ordered categories
- Y-Axis Numerical values
- Breakdown Axis Categorical data (each unique value becomes a separate line)
Description
- Lines - one line per category in the breakdown dimension, each drawn in a distinct color
- X-Axis - typically represents time or a sequential variable
- Y-Axis - represents the measured quantity
- Legend - maps each color to its corresponding category
When to Use a Grouped Line Chart
- Compare trends across categories - see whether two or more groups are converging, diverging, or moving in parallel
- Highlight seasonal or cyclical patterns - overlapping lines make recurring patterns immediately visible
- Track multiple KPIs together - useful when several metrics share the same scale and time range
- Spot outliers within a group - a single line that diverges from the others stands out clearly
When to Avoid a Grouped Line Chart
- Too many categories - more than 5–7 lines quickly become hard to read; consider filtering or aggregating
- Very different scales - if each series has a vastly different range, the smaller series will be flattened; use separate line charts instead
- Part-to-whole comparisons - use a stacked bar chart or grouped area chart when proportions matter
Further Reading
When to Use a Line Chart - a deeper look at line chart use cases, common mistakes, and alternatives.