Combo Chart
Overlays bars and lines with dual Y-axes to show volume and rate together.
Monthly Revenue & Growth Rate
Revenue ($K) as bars, growth rate (%) as line
View data (8 rows)
| Month | Revenue | Growth Rate |
|---|---|---|
| Jan | 120 | 5.20 |
| Feb | 135 | 12.50 |
| Mar | 148 | 9.60 |
| Apr | 162 | 9.50 |
| May | 155 | -4.30 |
| Jun | 178 | 14.80 |
| Jul | 195 | 9.60 |
| Aug | 210 | 7.70 |
Use a combo chart when…
- Comparing volume (bars) with a rate or trend (line)
- Revenue vs growth rate
- Sales volume vs conversion percentage
Avoid when…
- When both metrics share the same scale
- When a single axis chart is sufficient
Data it needs
| Property | Value |
|---|---|
| Min Rows | 4 |
| Min Columns | 3 |
| Column Types | stringnumbernumber |
| Notes | One column for bars, another for the line overlay. |
Visual anatomy
Guiding principles
- DesignChart-Question Fit
Combo chart answers 'how does volume relate to rate?'
- IntegrityShow Data Variation, Not Design Variation
Independent scales prevent misleading comparisons
- IntegrityZero Baselines
Anchor each axis's baseline deliberately — bar (volume) axis must start at zero; line (rate) axis can start at a meaningful reference (zero, 100% baseline) but never silently mid-range
Consider instead
Common mistakes
Dual axes with unrelated metrics that mislead
Not labeling which axis belongs to which series
History
Dual-axis charts emerged in business reporting in the 1990s, ubiquitous after Microsoft Excel's chart wizard made the overlay one click away.
Accessibility notes
Label both axes clearly. Distinguish bar and line series by color and shape. Provide data table.
Related reading
Got data? Let's see what works.
Drop your CSV. You'll get a Combo Chart plus four alternatives - ranked by which one actually fits your data best.