What is a Sankey Diagram?
A Sankey diagram is a flow visualization where the width of each arrow or band is proportional to the quantity it represents. Originally developed to illustrate steam engine efficiency, Sankey charts are now used across finance, engineering, ecology, and data analytics to make the magnitude of flows immediately visible at a glance.
Common use cases include personal and corporate budget analysis (showing where money comes from and where it goes), energy flow diagrams (tracking electricity or heat through a system), supply chain visualization (mapping materials from supplier to end product), and website traffic analysis (showing how visitors move between pages and where they drop off).
Because the link widths encode quantity, Sankey diagrams are especially effective when you need to compare many flows simultaneously and spot imbalances, bottlenecks, or dominant paths at a glance—something that tables and bar charts struggle to convey.
How to Use This Free Sankey Chart Maker
- Enter your data. Type or paste rows in the format Source, Target, Value into the data grid—one flow per row. For example: Salary, Rent, 1500.
- Load an example. Click "Load Example" to instantly populate the chart with a sample budget dataset so you can see the format in action before entering your own numbers.
- Adjust settings. Use the controls to switch color themes, toggle node labels, change the layout alignment, or switch between dark and light mode.
- Preview the diagram. The chart updates live as you edit—no need to click a render button. Zoom and pan on desktop by scrolling and dragging inside the chart area.
- Export your chart. Download the finished diagram as a PNG image, a scalable SVG file, or a self-contained interactive HTML file you can embed anywhere or share directly.
Frequently Asked Questions
Is Sankey Builder really free?
Yes. Sankey Builder is completely free to use with no usage limits, no watermark on exports, and no paywall. There is no paid tier—all features are available to everyone.
Do I need to create an account or log in?
No account or login is required. Open the page, enter your data, and download your chart. Nothing is stored on our servers.
What file formats can I export?
You can export your Sankey diagram as a PNG image (ideal for presentations and documents), an SVG vector file (scales to any size without loss of quality), or a self-contained interactive HTML file (can be embedded in a webpage or opened directly in any browser).
What data format does the tool accept?
Each row of data should contain three fields separated by commas: the source node name, the target node name, and a numeric value representing the flow magnitude. For example: Revenue, Taxes, 8000. You can also paste a CSV directly into the text import field.
Can I use this for commercial projects?
Yes. Charts you create and export are yours to use however you like, including in commercial reports, client deliverables, and published articles.
Free Online Sankey Chart Builder
Sankey Builder is a free browser-based tool for creating Sankey diagrams instantly. Paste your flow data, click Draw, and download your chart as PNG, SVG, or interactive HTML — no login, no account, no watermark, no paywall.
What is a Sankey Diagram?
A Sankey diagram is a type of flow visualization where the width of each arrow or ribbon is proportional to the quantity it represents. They're commonly used to show energy flows, budget breakdowns, supply chain movements, traffic sources, conversion funnels, and any process where values split or merge across stages.
How to Use Sankey Builder
Enter your data in the From / To / Value grid, or paste CSV directly. Click "Draw Chart" to render your diagram. Use the Export panel to download as PNG for presentations, SVG for editing in Illustrator or Figma, or HTML for an interactive shareable version with hover tooltips.
Why Sankey Builder?
Most Sankey chart tools are paywalled, require accounts, or add watermarks. Sankey Builder is completely free — no limits on nodes, no login required, and downloads are clean with no branding. It runs entirely in your browser with no data sent to any server.
Use Cases
Sankey diagrams are used across industries: supply chain and logistics teams use them to map product flows and identify waste; finance teams use them for budget and spend visualization; marketers use them for funnel analysis and traffic attribution; energy analysts use them to visualize resource conversion and losses; and data analysts use them to communicate complex multi-step processes clearly.
