Free Online Sankey Diagram Maker - Visualize Data Flows
Configuration
Flow Data
Define nodes (categories) and links (flows) to create your Sankey diagram. Links connect nodes and their width represents the flow value.
Nodes (Categories)
Links (Flows)
| Source Node | Target Node | Flow Value | |
|---|---|---|---|
Layout Settings
Display Options
Sankey Diagram Preview
What is a Sankey Diagram?
A Sankey diagram is a specialized flow chart that visualizes the flow of resources, energy, materials, or information between different stages of a process. Named after Irish engineer Matthew Sankey, these diagrams use proportional arrows or bands to show quantities, making it easy to identify the most significant flows and inefficiencies in complex systems.
Key Features of Our Sankey Diagram Maker
- Drag-and-drop interface for easy node and flow creation
- Customizable node colors and flow gradients
- Adjustable node width and spacing for optimal layout
- Show or hide node labels and flow values
- Real-time preview with smooth animations
- Export to PNG, SVG, or embed code
- No registration required - start creating immediately
When to Use Sankey Diagrams
Sankey diagrams excel at showing proportional relationships and identifying bottlenecks in flow-based processes. They're particularly effective when you need to track how quantities move through multiple stages or categories.
Common Use Cases:
- Energy flow analysis and consumption tracking
- Budget allocation and financial flow visualization
- Website traffic flow and user journey mapping
- Supply chain and logistics optimization
- Material flow in manufacturing processes
- Customer segmentation and conversion funnels
- Resource allocation in project management
Not Recommended For:
- Simple comparisons between categories (use bar charts instead)
- Time-series data visualization (use line charts)
- Hierarchical data structures (use tree diagrams)
- Geographic data representation (use maps)
Benefits of Using Sankey Diagrams
- Instantly identify the largest flows and most significant pathways
- Spot inefficiencies and bottlenecks in complex processes
- Communicate complex flow relationships in an intuitive visual format
- Track conservation principles and material balance
- Compare multiple flow scenarios side by side
- Engage stakeholders with compelling visual storytelling
- Support data-driven decision making with clear insights
How to Create a Sankey Diagram
Define Your Nodes
Start by adding nodes that represent the sources, processes, and destinations in your flow. Name each node clearly and assign colors for easy identification.
Create Flow Links
Add links between nodes by specifying the source, target, and flow value. The width of each flow will automatically adjust based on the value you enter.
Customize Appearance
Adjust node width, spacing, and colors. Choose between node-based coloring or gradient flows. Toggle labels and values based on your presentation needs.
Fine-tune Layout
Modify node padding and link transparency to optimize readability. Use animation settings to control how the diagram reveals information.
Export and Share
Download your diagram as PNG or SVG for presentations, or use the embed code to add it directly to websites and reports.
Tips for Better Charts:
- Keep node names concise but descriptive for better readability
- Use consistent color schemes to group related categories
- Start with major flows first, then add smaller details
- Test different node arrangements to minimize crossing flows
- Consider your audience when deciding whether to show exact values
Data Preparation Guidelines
Proper data preparation is crucial for creating effective Sankey diagrams. Your data should represent flows between distinct categories or stages.
Requirements:
- Identify all source, intermediate, and destination nodes
- Quantify flow values between each pair of connected nodes
- Ensure flow conservation - inputs should equal outputs for intermediate nodes
- Group similar categories to reduce complexity
- Validate that all flow values are positive numbers
- Check for circular flows that might confuse the layout
Data Format Examples
Energy Flow Analysis
Coal → Power Plant (500MW), Power Plant → Residential (200MW), Power Plant → Industrial (300MW)
Budget Allocation
Total Budget → Marketing ($50K), Marketing → Digital Ads ($30K), Marketing → Print Ads ($20K)
Website Traffic
Organic Search → Homepage (1000 visits), Homepage → Product Pages (600 visits), Homepage → About (400 visits)
Technical Implementation Guide
Browser Compatibility
Our Sankey diagram maker works in all modern browsers including Chrome, Firefox, Safari, and Edge. The tool uses HTML5 Canvas and SVG for rendering, ensuring smooth performance across desktop and mobile devices.
Performance Optimization
- Limit diagrams to 50-100 nodes for optimal performance
- Group small flows into 'Other' categories to reduce complexity
- Use shorter node names to improve rendering speed
- Consider breaking very complex flows into multiple diagrams
- Export large diagrams as SVG for better scalability
Integration Options
- Embed interactive diagrams directly in web pages using provided code
- Export static images for use in presentations and reports
- Generate SVG files for further editing in design software
- Use PNG exports for social media and documentation
- Link to your diagram for real-time collaboration
When to Consider Alternative Chart Types
Flowchart
When to use: When you need to show decision points and process logic rather than proportional flows
Advantage of Free Online Sankey Diagram Maker - Visualize Data Flows: Better for representing complex branching processes and workflows
Alluvial Diagram
When to use: When tracking how categorical data changes over time or across multiple dimensions
Advantage of Free Online Sankey Diagram Maker - Visualize Data Flows: Shows changes in composition and category membership over time
Network Diagram
When to use: When relationships between entities are more important than flow quantities
Advantage of Free Online Sankey Diagram Maker - Visualize Data Flows: Better for showing complex interconnections and network topology
Treemap
When to use: When you need to show hierarchical proportions without flow relationships
Advantage of Free Online Sankey Diagram Maker - Visualize Data Flows: More efficient use of space for displaying proportional data
Common Issues and Solutions
Problem: Flows appear too narrow or wide
Solution: Adjust the node width setting to change the overall scale of flows, or check that your flow values are in appropriate ranges
Prevention: Normalize your data to consistent units before creating the diagram
Problem: Node labels are overlapping
Solution: Increase node padding to create more space between nodes, or reduce label font size in display settings
Prevention: Use shorter, more concise node names from the start
Problem: Flows are crossing and creating visual clutter
Solution: Reorder nodes by dragging them to different positions, or group related nodes together
Prevention: Plan your node arrangement before adding flows, grouping sources on one side and destinations on the other
Problem: Diagram doesn't show expected flow conservation
Solution: Check that intermediate nodes have equal input and output flows, or add missing connections
Prevention: Validate your data for flow conservation before creating the diagram
Advanced Visualization Techniques
Color Coding Strategies
Use consistent colors to represent different types of flows (e.g., renewable vs. non-renewable energy) or assign colors based on efficiency levels to highlight areas for improvement.
Multi-Stage Analysis
Create multiple Sankey diagrams for different time periods or scenarios, then compare them to show how flows change over time or under different conditions.
Nested Flow Representation
Start with a high-level overview, then create detailed diagrams for major flow categories to provide both summary and detailed views of your system.
Interactive Storytelling
Use the animation features to reveal flows progressively, building a narrative that guides viewers through your analysis step by step.
Industry Applications
Energy Sector
Track energy production from various sources through distribution networks to end consumers
Identify energy losses and optimize distribution efficiency
Manufacturing
Visualize material flows through production processes and identify waste streams
Reduce waste and improve resource utilization
Digital Marketing
Map customer acquisition channels through conversion funnels to sales outcomes
Optimize marketing spend and improve conversion rates
Supply Chain
Track product flows from suppliers through warehouses to retail locations
Identify bottlenecks and optimize inventory distribution
Finance
Show how investment funds flow through different asset classes and geographic regions
Communicate portfolio allocation and risk distribution to stakeholders
Frequently Asked Questions
A good Sankey diagram clearly shows proportional relationships with minimal crossing flows. Use consistent colors, clear labels, and ensure flow conservation. Start with major flows and add details gradually. Keep the layout simple and intuitive for your audience.
For intermediate nodes, the sum of input flows should equal the sum of output flows. Use a spreadsheet to validate your data before creating the diagram. Our tool will automatically size flows proportionally, but you need to ensure the underlying data follows conservation principles.
Traditional Sankey diagrams only show positive flows. For losses or waste, create separate nodes (like 'Heat Loss' or 'Waste') and show flows to these destinations. This maintains the visual integrity while accounting for all inputs and outputs.
Node colors assign a single color to each category, with flows taking the color of their source node. Flow gradients blend colors from source to destination, creating a rainbow effect that can help trace individual flows but may be less readable with many connections.
While there's no hard limit, diagrams with more than 20-30 nodes become difficult to read. For complex systems, consider creating multiple diagrams for different aspects or time periods, or group smaller flows into 'Other' categories to maintain clarity.
Yes, our tool includes animation controls that let you adjust how the diagram builds and transitions. Use animations to reveal information progressively or to smooth transitions when updating data. Adjust the animation speed to match your presentation pace.
You can export your Sankey diagram as PNG for presentations and documents, SVG for scalable graphics and further editing, or get embed code to add interactive diagrams to websites. All exports maintain the quality and customization of your original design.
Small flows can be grouped into an 'Other' or 'Miscellaneous' category to reduce clutter. Alternatively, use the minimum flow width setting to ensure even small flows remain visible, or create a separate detailed view for minor flows.