How to make a bubble chart
- Rename the X, Y and Bubble size headers to describe your variables.
- Enter one row per bubble with its position (X, Y), size and, optionally, a label and group.
- Set the largest bubble radius in Customize → Chart options so bubbles don’t overlap too much.
- Lower the opacity if bubbles overlap, and turn labels on or off.
- Add axis titles, then download.
Data format
| Column | Type | Notes |
|---|---|---|
| Label | Text | Optional |
| X | Number | Required |
| Y | Number | Required |
| Bubble size | Number (zero or positive) | Required |
| Group (optional) | Text | Optional |
Up to 1,000 rows. One row per bubble: its position (X, Y) and a third value for size. Bubble AREA is proportional to the size value, so a value twice as large gets a bubble with twice the area — not twice the diameter. Sizes cannot be negative.
Customization options
- Area-accurate sizing: bubble area, not diameter, is proportional to the size value.
- Maximum bubble radius and opacity.
- Group colors with a legend, and labels drawn inside or above bubbles.
- Axis limits, gridlines and an optional trendline.
- Smaller bubbles are drawn on top of larger ones so none are hidden.
Downloading and exporting
- PNG: best for slides, documents and the web. It supports transparent backgrounds, and you can choose standard, 2×, 4× or slide-sized (1920 × 1080) output.
- JPEG: a smaller file with a solid background.
- SVG: a true vector file. It stays sharp at any size and can be edited in Illustrator, Inkscape or Figma.
- PDF: vector PDF sized to the chart, A4 or US Letter. If your labels use characters outside the standard PDF fonts (for example Chinese, Arabic or emoji), the PDF uses a high-resolution image instead and tells you.
- CSV and .json: your data, or the whole chart with its settings, to re-open later.
When to use a bubble chart
- Comparing items on three numeric measures, such as countries by income, life expectancy and population.
- Portfolio or opportunity maps: market size vs. growth, with revenue as bubble size.
- Showing clusters where magnitude also matters.
When to choose a different chart
- Size differences are small. People judge area poorly, so if precise comparison of the third variable matters, use a bar graph.
- You have hundreds of points. Bubbles overlap heavily; use a scatter plot or a heatmap.
- Values can be negative. Bubble sizes must be zero or positive.
Common mistakes to avoid
Scaling diameter instead of area
If a value twice as large gets twice the diameter, its bubble has four times the area and looks far bigger than it should. This tool always scales by area.
No size legend in the caption
Readers can’t tell what bubble size means unless you say so. Name the size variable in the subtitle, for example “Bubble size = population (millions)”.
Too many labels
Label only the bubbles you discuss. Turn labels off and rely on tooltips while exploring.
Practical examples
Income and health
GDP per capita (X), life expectancy (Y) and population (size) for seven fictional countries, colored by region.
Product portfolio
Market growth (X), profit margin (Y) and revenue (size) to identify stars and underperformers.
Sales territories
Number of customers (X), average order value (Y) and total sales (size) per territory.
Why bubble area matters
The eye reads a circle’s size by its area. Radius is therefore calculated as √(value ÷ max) × maximum radius. A value of 25 gets a bubble with exactly a quarter of the area of a value of 100, with half the diameter. A zero-sized value is drawn as a tiny dot so it remains visible and hoverable.
Frequently asked questions
Can I color bubbles by category?
Yes. Fill in the Group column. Each group gets a color and a legend entry.
Can bubble size be negative?
No. A circle can’t have a negative area, so negative sizes are flagged as errors. Use the Y-axis for signed values instead.
How do I stop bubbles overlapping?
Reduce “Largest bubble radius”, lower the opacity, or widen the axis limits.
Is a bubble chart the same as a scatter plot?
It is a scatter plot with one extra variable encoded as size. Without size data, use the scatter plot maker.
What is the maximum number of bubbles?
1,000 per chart, though charts are clearest with fewer than about 50.
Your data stays private
Charts are drawn by your browser. Your data isn’t uploaded to our servers; it is kept only in this browser’s storage, for autosave and saved charts, until you clear it. See our privacy policy.