How to Make a Sankey Diagram in 2026

You have data that flows. Customers through a funnel, money through departments, energy through a grid. You need a diagram that shows where things go and how much. That’s a Sankey diagram, and making one is simpler than you think.

This guide walks you through creating a Sankey diagram from scratch, regardless of what your data looks like or where it lives.

Step 1: Understand the format

A Sankey diagram needs three things per flow: a source, a target, and a value. That’s it.

Think of it as answering: “How much of X goes to Y?”

• Sales [45000] Salaries
• Sales [12000] Travel
• Engineering [82000] Salaries
• Engineering [34000] Cloud Services

Each line is one flow. The source is on the left, the value is in brackets, and the target is on the right. When a target appears as a source in another line, the flows chain together. That’s how you build multi-level diagrams.

Step 2: Get your data ready

Your data probably lives in one of these formats:

Already know your flows

If you can write down “X sends Y amount to Z,” you’re ready. Just type it out:

Website [3200] Product Page
Website [1800] Pricing
Product Page [2200] Sign Up
Product Page [1000] Exit
Pricing [1400] Sign Up
Sign Up [2800] Active User
Sign Up [800] Churned

Data in a spreadsheet

If your data is in Excel or Google Sheets with columns like Source, Target, and Value, copy those three columns and paste them into a CSV import tool. Most Sankey tools can parse CSV with headers.

Messy or unstructured data

Real-world data is rarely clean. You might have a report with tables, notes, and calculations mixed together. Some tools can handle this. Sankey Flow Studio has a cleanup feature that transforms messy pasted data into the right format automatically.

Data in a screenshot

Sometimes your data is locked inside an internal tool with no export option. If you can screenshot the table, some tools can read the image and extract the flow data for you.

Step 3: Choose your tool

There are several options depending on your needs:

For a quick one-off diagram: SankeyMatic is free, runs in the browser, and requires no account. Limitations: no saving, one color palette, manual formatting only.

For ongoing use with cloud saves: Sankey Flow Studio offers cloud storage, 14 color palettes, smart contrast for label readability, and data cleanup tools. Free tier available.

For developers: D3.js with the d3-sankey plugin gives you full control. Requires JavaScript knowledge.

For enterprise teams already using BI tools: Power BI and Tableau both support Sankey diagrams through plugins, though setup is more involved.

Step 4: Paste and render

In most browser-based tools, the workflow is the same:

1. Open the tool
2. Paste your data in the Source [Value] Target format
3. The diagram renders automatically

If your diagram looks crowded, adjust these settings: - Node padding · increase the vertical spacing between nodes - Canvas height · give the diagram more room to breathe - Font size · reduce if labels are overlapping - Wrap width · controls how many characters before a label wraps to a new line

Step 5: Choose a color palette

This is where most people stop thinking, and it’s where the best diagrams stand out.

Default rainbow colors make every diagram look the same. A thoughtful palette makes your data feel intentional. Consider what story you’re telling:

• Professional reports: Muted earth tones or slate palettes convey seriousness without being boring
• Presentations on a projector: Bold, high-contrast palettes (or neon palettes on a dark canvas) ensure readability from the back of the room
• Accessibility: Look for palettes designed for color vision deficiency. They use brightness and saturation variation, not just hue

Some tools offer multiple palettes. Sankey Flow Studio includes 14, ranging from bold categorical palettes to Japanese-inspired color theory palettes like Wabi and Ukiyo-e that emphasize subtlety and natural tones.

Step 6: Reposition nodes

The algorithm that lays out a Sankey diagram optimizes for minimal link crossings, but it doesn’t know your story. You might want a particular node higher or lower to emphasize a flow path.

Look for a drag-to-reposition feature. Grab any node and move it vertically. The links will redraw in real time. This is often the difference between a diagram that’s technically correct and one that actually communicates.

Step 7: Export

Most tools support SVG and PNG export:

• SVG · vector format, scales to any size without losing quality. Best for reports, documents, and web embedding.
• PNG · raster format at a fixed resolution. Best for slides, social media, and quick sharing. Look for a 2x or 3x export option for higher resolution.

If you’re presenting on a large screen, always export at 2x or higher. A 1x PNG will look blurry when projected.

Tips for better Sankey diagrams

Keep it under 20 nodes. More than that and the diagram becomes hard to read. If you have more, consider grouping smaller categories into an “Other” node.

Name nodes clearly. “Resolved” is better than “Status Code 4.” “Digital Ads” is better than “Marketing Channel A.” Your audience shouldn’t need a legend.

Show values, not just flows. Absolute numbers or percentages on the labels help the audience understand scale without counting pixels.

Use dark canvas for presentations. A dark background with bright nodes and flows looks dramatically better on a projector or screen share than a white background.

Let the width of the flows tell the story. The whole point of a Sankey is that the thickness of each flow is proportional to its value. If one flow dominates, that’s not a design problem. That’s the insight. Don’t try to minimize it.

Common mistakes

Circular flows. If Node A flows to Node B and Node B flows back to Node A, most Sankey tools will break. Sankey diagrams are directional. They flow left to right. If your data has cycles, you’ll need to break them by treating the return flow as a separate node (e.g., “Returns to A”).

Unbalanced data. If a node receives 100 units but only sends out 80, the diagram will look uneven. Make sure your inflows equal your outflows for intermediate nodes. Only the leftmost (sources) and rightmost (endpoints) nodes should have unmatched flows.

Too many colors. If every node is a different bright color, nothing stands out. Use color intentionally. Group related nodes in similar hues, or use a muted palette and let the flow widths carry the visual weight.

Start making

The fastest way to learn is to try it. Grab some data, even if it’s made up, and paste it into a tool. You’ll understand how Sankey diagrams work in about thirty seconds of seeing your data rendered as flowing connections.

If you don’t have data handy, try this:

Morning Coffee [200] Home Brew
Morning Coffee [150] Coffee Shop
Morning Coffee [50] Office Machine
Home Brew [120] French Press
Home Brew [80] Pour Over
Coffee Shop [100] Latte
Coffee Shop [50] Drip
Office Machine [30] Acceptable
Office Machine [20] Regrettable

Paste that into Sankey Flow Studio, pick a palette, and drag the nodes around. You just made your first Sankey diagram.

Sankey Flow Studio is free forever. 14 color palettes, smart contrast, cloud saves, and intelligent data cleanup. Try it now. No credit card required.