Online Heatmap Maker (Clustered Heatmap)

Paste a gene expression matrix to draw a clustered heatmap with row z-scores, dendrograms and a sample group bar, then export SVG / PNG.

Everything runs locally in your browser. Pasted data is never uploaded to any server.

Choose file

One group name per sample in column order (one per line, or comma-separated), or one “sample name + Tab + group” per line. Leave empty for no groups.

Group colors

All (top 2000 by variance if there are more)Top N by varianceMy gene list

ScalingColor scalez-score minz-score maxDistanceRow names (genes)Width (mm)Title

Cluster rows (genes)Cluster columns (samples)Italic gene namesShow column names (samples)

Paste your data, or click “Load example” to try it out.

Row z-score: each gene (row) has its mean across samples subtracted and is divided by its standard deviation (n − 1 denominator, as in R’s scale), so colors show relative levels of one gene across samples, not absolute levels between genes. Values outside the color range get the end colors (default -1 to 1, as on the platform).
Clustering: hierarchical, complete linkage (pheatmap default), with Euclidean or 1 − Pearson distance; the algorithm is ported from R’s hclust and gives the same result for the same distances, but distances can differ from R in the last digits, so with many exact ties (e.g. very low integer counts) the tree may differ slightly from pheatmap. With z-scores, clustering uses the unclipped z-scores. Rows are clustered and columns are not by default (keeping the sample order), as on the platform.
Rows with missing values are removed; above 2000 genes, the 2000 with the highest variance are kept. Normalized, log-scale input (e.g. VST, log2 CPM / TPM) is recommended.
The TSV is the matrix actually drawn: unclipped z-scores (when scaling), rows and columns in plot order. Layout follows the platform figure style (Arial, 6 pt text); width 89 or 183 mm.