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Bubble Chart Maker

Three variables, one chart: position for two of them, bubble size for the third. Upload your data, map the columns, and publish an interactive bubble chart you can embed anywhere — free.

Create a Bubble Chart — freeSee the gallery

What is a Bubble Chart?

A bubble chart is a scatter plot with a third variable encoded as the area of each mark. Two numeric columns set the position, a third sets the size, and an optional category sets the colour — four dimensions of data in one flat picture. That density is the appeal and also the risk: area is read far less accurately than position, so the size variable should be context rather than the finding you are asking the reader to measure.

When to use a Bubble Chart

  • You have a third variable that adds weight, not precision

    Revenue against margin sized by headcount; admission rate against applicants sized by class size. The size says "this one matters more" without needing to be read off a scale.

  • You want to show that big things behave differently

    Bubble charts are good at revealing that the large entities cluster in one part of the space and the small ones somewhere else — a pattern a plain scatter plot leaves implicit.

  • You are plotting a moderate number of entities

    Roughly ten to sixty bubbles is the sweet spot. Enough to see structure, few enough that the marks do not swallow each other.

  • You need one chart to carry a whole comparison

    For a slide or an embed where you get a single picture, a bubble chart packs the most information per square inch of any standard chart type.

When not to use a Bubble Chart

  • The reader must compare the third variable precisely

    People judge area poorly and inconsistently. If the size values need to be ranked or measured, put that variable on an axis and use a plain scatter plot or a bar chart.

  • Your size values span several orders of magnitude

    One bubble covering the plot while the rest are dots communicates nothing. Either filter, or scale the size variable explicitly and say so on the chart.

  • Your size variable can be negative or zero

    Area has no natural way to show a negative number. Encode that variable with colour or position instead.

  • You have hundreds of records

    Bubbles overlap far more aggressively than points. At high counts, drop to a scatter plot with small marks and transparency.

How to make a Bubble Chart

From a spreadsheet to a published chart, step by step.

01

Start from the bubble chart template

Open the PlotSet bubble chart template. It loads with sample data bound so you can see which columns the chart expects before you upload your own.

02

Prepare three numeric columns

One row per entity, with a label column plus three numeric columns: X, Y and size. Add a category column if you want the bubbles coloured by group.

03

Upload or connect your data

Import a CSV or Excel file, paste directly from a spreadsheet, or connect a Google Sheet to keep the chart refreshable.

04

Map the columns and tune the size scale

Assign X, Y and size, then adjust the size range until the largest bubble is prominent without hiding its neighbours. Scale by area, never by radius — radius scaling exaggerates every difference.

05

Label, publish and embed

Label the bubbles that carry the story and leave the rest to tooltips, then publish a live interactive embed or export a PNG, SVG or PDF.

Start from the Bubble Chart template with sample data already loaded, then swap in your own.

Open the template

The parts of a Bubble Chart

X axis
The horizontal numeric scale — the first of the two variables read by position, and therefore read accurately.
Y axis
The vertical numeric scale, carrying the second position variable.
Bubble area
The third variable, encoded as area. Area is approximate by nature: it conveys magnitude and importance, not exact values.
Colour
An optional fourth dimension, almost always a category — region, segment, sector — used to group bubbles visually.
Size legend
Two or three reference bubbles with values attached. Without it the size encoding is decorative, because the reader has no scale to map area back to numbers.
Label / tooltip
The identity of each bubble. Direct labels for the important few, tooltips for the rest, so the chart stays legible.

Common Bubble Chart mistakes

Scaling bubbles by radius instead of area

Doubling the radius quadruples the area, so radius scaling makes a 2× difference look like 4×. Area scaling is the only honest option.

Omitting the size legend

If the reader cannot tell whether a big bubble means 100 or 100,000, the third variable is decoration. Always ship a size legend.

Letting large bubbles hide small ones

Draw the largest bubbles first so smaller ones land on top, add transparency, and cap the maximum size so one record cannot own the canvas.

Encoding a category as size

Size is a quantitative channel. Mapping a non-numeric variable to it implies an order and a magnitude that do not exist.

Bubble Chart: common questions

Showing three variables at once: two by position on the X and Y axes and a third by the area of each bubble. It is the standard choice when a scatter plot is right but one more measure needs to be visible.

Make your Bubble Chart now

Free to start with 300+ templates. No credit card required.

Create a Bubble Chart — freeAll chart types