Heatmap Maker
Paste a matrix of values to build a heatmap, where each cell's colour encodes its magnitude. Use a header row for column names and a first column for row names — ideal for correlation matrices or expression data.
How it works
A heatmap represents a two-dimensional matrix of numbers as a grid of coloured cells, where colour encodes the value. It makes patterns — clusters, gradients, outliers — jump out of a table of numbers, which is why it is a staple for gene-expression matrices, correlation tables and any dense grid of measurements. Paste your data with a header row of column names and a first column of row names; the remaining cells are the numeric values, mapped onto a colour scale from low to high.
The colour legend is calculable, so you can see exactly which value each colour represents, and the chart re-colours its axes for light and dark themes. Data can be comma-, tab- or space-separated for easy pasting, and small matrices also show the value inside each cell.
Examples
- A gene-by-sample matrix reveals expression patterns at a glance.
- Warmer colours mark higher values, cooler colours lower ones.
- The first column names the rows and the header row names the columns.
Frequently asked questions
- What data does a heatmap need?
- A matrix: a header row of column names, a first column of row names, and numeric values in the cells. Every cell's value is mapped to a colour.
- What do the colours mean?
- Colour encodes magnitude on a continuous scale from the minimum to the maximum value in your data. The legend shows exactly which value each colour represents.
- What is a heatmap good for?
- Spotting patterns in dense grids of numbers — gene-expression matrices, correlation tables, activity-by-hour grids — where clusters and outliers are hard to see in raw figures.
- Is my data private?
- Yes. The heatmap is generated in your browser and your data never leaves your device.