A bubble chart extends the scatter plot by adding a third dimension: each point's area represents a numeric value, turning dots into bubbles. It is ideal for comparing three variables simultaneously on a single plot.
Planets Compared — Distance × Diameter × Moon Count
Best for
- Comparing three numeric dimensions at once (x, y, size)
- Highlighting relative magnitude alongside position
- Visualising countries, products, or entities with multiple metrics
Avoid when
- Bubble sizes vary so much that small ones become invisible
- You have more than 20–25 data points — chart becomes cluttered
- The size dimension is not meaningful — use a plain scatter plot
Alternatives: Scatter Plot