Heatmap Chart
Free Online Heatmap Chart Maker
What is a Heatmap Chart?
A heatmap chart uses a color-coded matrix to display values across two dimensions — rows and columns — so patterns, hotspots, and outliers surface immediately without reading individual numbers. Each cell's color intensity maps directly to its value, letting you compare dozens of data points at once. Use a heatmap when you need to reveal correlations, seasonal trends, or performance gaps across categories that would be invisible in a bar or line chart.
Key Features
9 Built-in Color Schemes
Choose from Viridis, Plasma, Turbo, Reds, Blues, and more — or set your own custom min and max colors to match your brand or highlight specific value ranges.
Row and Column Labels
Label both axes clearly so every cell is uniquely identifiable. Toggle row labels, column labels, or both depending on your layout.
Cell Value Display
Optionally show numeric values inside each cell for precise reading alongside the color encoding, with adjustable font sizes.
Interactive Tooltips
Hover over any cell to see its exact value without adding clutter to the visual — ideal for dense matrices with many data points.
Adjustable Cell Layout
Control cell size, gap, border width, border radius, and border color to fit any data density and presentation context.
Color Legend
A built-in legend maps color to value ranges so readers can decode the scale independently. Position it at the top, bottom, left, or right.
Best For
When to Use
- Your data is organized by two categorical dimensions (rows × columns)
- You want to reveal patterns visually rather than through a table of numbers
- You have too many values to compare individually with bar or line charts
- You need to highlight hotspots, gaps, or outliers across a matrix
- Readers need to spot trends across both dimensions simultaneously
- Color encoding communicates the story faster than exact numbers
Common Mistakes
- !Using too many rows or columns, making cells too small to read or interact with
- !Choosing a color scheme with poor contrast that doesn't work for colorblind readers
- !Omitting the color legend, leaving readers unable to decode what the colors mean
- !Placing categories with no natural ordering on the axes, which hides meaningful patterns
- !Comparing groups of very different sizes without normalizing the values first
- !Showing raw counts when percentages would make cross-row comparisons fair
Related Tools
Create similar charts with these tools
Free Heatmap Chart Generator — MakeCharts
Create stunning heatmap charts in seconds. Visualize patterns, correlations, and density across rows and columns. Free, no sign-up required. Try it now.
Free Correlation Heatmap Maker | MakeCharts
Create correlation heatmaps instantly. Map data relationships with color-coded cells, custom schemes, and AI generation. Free, no signup required.
Free Heatmap Maker — Build Heat Maps Online
Create stunning heatmaps in minutes. Our free heat map maker lets you visualize data density, patterns, and correlations with customizable colors and layouts.
Free Hexbin Heatmap Maker | MakeCharts
Build professional hexbin heatmaps instantly. Reveal density patterns, correlations, and intensity across rows and columns — no design skills needed.
Templates
Start with professionally designed templates
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Correlation Heatmap Template
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Visualize conversion factors between mg, g, kg, oz, lb, and t in a color‑coded matrix for fast, error‑free cross‑unit lookups.
View All Templates
Browse the full library to find more templates tailored to your chart.