Free Online Sankey Diagram Maker
Make a Sankey diagram free online, no signup — paste source, target, and value rows to draw flow bands sized to each quantity, then export PNG, SVG.
Create Your Sankey Diagram Now — It's FreeWhat Is a Sankey Diagram?
What Data You Need for a Sankey Diagram
A Sankey diagram needs one label column written as "Source > Target" (separators >, ->, or → all work) plus one numeric value column for the flow size. Nodes are created automatically from the names, and chains like "A > B > C" in a single label are split into A→B and B→C flows. Example rows: "Revenue > Salaries" 420, "Revenue > Marketing" 180, "Marketing > Profit" 60.
When to Use a Sankey Diagram
Where a Sankey Diagram Works Best
- Energy and resource accounting — tracing how fuel inputs split into useful work, electricity, heat, and losses across conversion stages.
- Budget and revenue breakdowns — showing how total revenue or income divides into departments, cost categories, taxes, and net profit in one view.
- User journey and conversion funnels — mapping how visitors flow from acquisition channels through pages to signup or drop-off.
- Supply-chain and material flow — visualizing how raw input quantities split across processes, products, byproducts, and waste streams.
Sankey Diagram Example: Household Budget Flow
A household maps where its monthly income comes from and where it goes.
Sample data: "Source > Target" labels + a value column: Salary > Total Income 5000; Side Income > Total Income 1000; Total Income > Housing 1800; Total Income > Food 900; Total Income > Transport 600; Total Income > Savings 1200.
Total Income is the hub; Housing is the largest outflow at 1800, and Savings captures 1200 of the 6000 total.
How to Create a Sankey Diagram Online
- Step 1: Open ChartLoad and select Sankey Diagram from the chart type picker
- Step 2: Define your nodes by entering source names, target names, and the flow values between them
- Step 3: Add multiple rows to build multi-stage flows with intermediate nodes connecting sources to destinations
- Step 4: Adjust node positions, band colors, and opacity to improve readability and visual appeal
- Step 5: Add labels and tooltips so viewers can identify exact flow quantities at each connection
- Step 6: Click Export to download your Sankey diagram as PNG, PDF, or SVG
Sankey Diagram Best Practices & Tips
- Keep flow direction consistent — typically left-to-right for processes and top-to-bottom for hierarchies.
- Limit nodes to 15-20 total; beyond that, the diagram becomes a dense web of crossing flows.
- Use color to distinguish source categories so each flow stream is traceable through the entire diagram.
- Label flow widths with exact values to add precision to the visual proportional encoding.
- Sankey diagrams cannot show cycles — ensure your data describes a directed, acyclic flow process.
- Test readability by checking that flow labels do not overlap — use hover tooltips for dense diagrams.
- Sankey diagrams are powerful for energy flow audits, website user journey analysis, and budget allocation tracking.
- When showing energy or budget flows, annotate the largest ribbon with its exact value and percentage so the dominant flow path is quantified precisely, not merely visually prominent.
Common Sankey Diagram Mistakes to Avoid
- Unbalanced nodes: if a node takes in 500 but only sends out 300, the missing 200 silently disappears and band widths mislead. Add an explicit 'Loss' or 'Remainder' target so inflow equals outflow.
- Adding cycles or loops (A to B and B back to A). Sankey layouts assume directed, acyclic flow left to right; a feedback loop produces tangled, unrenderable bands. Use a chord diagram or network graph for circular flows.
- Too many thin, near-equal flows so every band looks the same width. Sankey only reads clearly when a few flows dominate; aggregate small categories into an 'Other' node and keep total nodes under about 20.
- Reusing the same name for a source and a later target stage, which merges what should be separate nodes. Give each stage a distinct label (e.g. 'Coal (input)' vs 'Coal (loss)') so the flow path stays traceable.
Frequently Asked Questions
Is this Sankey diagram maker free?
Yes, it is 100% free with no signup, no watermark, and no usage limits. You can build a Sankey chart in your browser and export it as PNG, SVG, or PDF at no cost.
What data do I need to make a Sankey diagram?
You need a list of flows, each with three values: a source node, a target node, and a numeric flow value. The tool builds the nodes and proportional bands automatically — for example, source 'Revenue', target 'Salaries', value 420.
How do I make a Sankey diagram in Excel?
Excel has no native Sankey chart type, so you would need a third-party add-in or manual workarounds. It is faster to paste your source-target-value rows into this online Sankey generator and export the image directly.
What is the difference between a Sankey diagram and an alluvial diagram?
Both use proportional flow bands, but a Sankey shows directed flow of a quantity through a process (energy, money, traffic), while an alluvial diagram tracks how categorical groups regroup across dimensions or over time. Sankey emphasizes magnitude and conservation; alluvial emphasizes how categories reshuffle.
Can a Sankey diagram have multiple stages or levels?
Yes. Add intermediate nodes by making a target in one row the source in another, building multi-stage flows from origin through several steps to a final destination. Keep the flow directed left to right with no loops.
Related Chart Types
Ready-Made Sankey Diagram Templates
Skip the blank canvas — open a free, editable Sankey Diagram template, swap in your own data, and export. Browse all templates.
Ready to Create Your Sankey Diagram?
No signup. No watermark. 100% free.
Start Creating Now