Chord Diagram Generator - Free Online Circular Chart Maker

A free online chord diagram generator. Upload CSV data to create a colorful circular chord diagram and download high-resolution PNG / SVG images (watermark-free). The page comes preloaded with sample data of flows between 50 countries, so you can see the result as soon as you open it.

1. What is a chord diagram?

A chord diagram is a circular data visualization that shows the flow or strength of relationships between multiple categories. Its name comes from the geometric “chord” — a line segment whose endpoints lie on a circle. In data visualization, categories are arranged around the circumference as colored arcs, and the wider the connecting bands (chords) between them, the greater the relationship or flow they represent.

The core value of a chord diagram lies in its ability to answer the key question intuitively: who is flowing to whom, and how much? Compared with traditional tables or bar charts, a chord diagram condenses complex many-to-many relationships into a single circular layout, letting viewers see at a glance which nodes are closely connected and which flow is the strongest.

Technically, a chord diagram can be seen as a variant of the arc diagram — a visualization method that shows interrelationships within a matrix. Nodes are arranged radially around the circle, and links between them are drawn as weighted (width-bearing) arcs. This design makes chord diagrams especially well suited for comparing similarities between datasets or across different groups of data.

2. Main application scenarios

Chord diagrams are widely used wherever you need to show complex relationships between multiple entities:

• Trade and population flows: trade volumes, capital flows, and migration between countries or cities — for example, global import/export trade relationships or intercity migration flows.
• Social network analysis: follows, reposts, and interactions between users, as well as information diffusion paths within communities. A chord diagram clearly shows the interaction intensity between core and peripheral nodes in a social network.
• Bioinformatics and genomics: association strength and co-occurrence between species or genes. In the life sciences, chord diagrams are widely used to visualize genomic data.
• Business management and organizational analysis: collaboration frequency, knowledge flow, and communication density between departments. Managers can use it to identify information silos or collaboration hubs within an organization.
• Text and co-occurrence analysis: keyword co-occurrence networks and author collaboration maps. In academic literature analysis, chord diagrams are often used to show connections between research hotspots.

3. What do the numbers in the chart mean?

The numeric tick marks in a chord diagram sit in the blank area just inside the colored outer arcs, and they represent the cumulative flow along that node’s arc segment. Specifically:

• The scale runs from 0 up to the node’s total inflow and outflow, in the same unit as the value column of your uploaded CSV data.
• Arc length is proportional to flow — the longer a node’s outer arc, the greater its total inflow and outflow.
• Ribbon width is proportional to flow — the wider the ribbon between two nodes, the larger the flow between them.

In short: read the outer arc length to judge a node’s total flow, and read the ribbon width to judge the strength of pairwise relationships. To focus on the main relationships, simply ignore the thin ribbons and read only the thickest few. For symmetric matrix data (such as two-way counts), the diagram draws bidirectional ribbons, which you can tell apart by directional colors (if available).

4. How to use this tool

4.1 Data preparation

This tool accepts three-column CSV data: source,target,value.

• source (source node): the originator of the relationship, such as a country name, username, or department name
• target (target node): the receiver of the relationship
• value (flow value): the size of the flow between the two, such as trade volume or number of interactions

Limits: up to 200 rows and 60 nodes. Data with or without a header row is accepted.

Example CSV data format:

source,target,value
China,Japan,380
China,USA,460
Germany,France,340

4.2 Steps

1. Open the page: visit the tool page and you’ll immediately see the built-in sample chord diagram of flows between 50 countries.
2. Upload your data: drag and drop a CSV file into the designated area, or click the “Click to upload” button to choose a file. You can also click “Load sample” first to try it out.
3. Choose a color theme: the tool offers three color themes — Classic / Rainbow / Morandi. Switch with one click to restyle the chart; light and dark display modes are also supported.
4. Export the image: click “Download PNG” or “Download SVG” to save the image. PNG is exported at 2x high resolution and SVG is a scalable vector graphic — both watermark-free.

4.3 Key features

• 100% free, with no usage limits
• No registration or login required
• Runs directly in your browser — nothing to download or install
• All data is processed locally and never uploaded to any server, fully protecting your privacy

5. Frequently asked questions (FAQ)

Q1: Does the data for a chord diagram have to be three columns — source, target, value?

Yes. The tool accepts three-column CSV data (source, target, value), up to 200 rows and 60 nodes. A header row is optional.

Q2: Which file formats are supported?

.csv text files are supported.

Q3: What are the data size limits?

Up to 60 nodes and 200 relationships.

Q4: What is the quality of the exported images?

PNG is exported at 2x high resolution, and SVG is a freely scalable vector format. Neither carries a watermark.

Q5: Will my data be uploaded to a server?

No. All data processing happens entirely in your local browser and is never uploaded to any server.

Q6: Why do the ribbons in a chord diagram have directions?

For symmetric matrix data (such as two-way counts), the diagram draws bidirectional ribbons, which you can distinguish by directional colors (if available).

Q7: What should I do if too many nodes make the chart look crowded?

If you have many nodes, focus on the main relationships — ignore the thin ribbons and read only the thickest few to quickly grasp the core information.

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Last verified: 2026-09-10