01
Business Reports
Compare performance across teams, regions, products, or time periods—and export a clean visual for your next deck.
Free No sign-up. No server uploads.
Charttoolbox
Free Heatmap Generator
Use Charttoolbox to turn CSV, Excel, or pasted data into a clear, customizable heatmap. Create correlation matrices and export publication-ready PNG or SVG files—all in your browser.
✓ CSV & Excel✓ Automatic correlation✓ 100% private
Your workspace
Create a heatmap from your data
Start with your own spreadsheet or explore a ready-made example.
Browser workspace
Your data stays on this device
Drop your spreadsheet here
CSV, XLSX, or XLS · up to 10 MB and 20,000 cells
or start with a sample
Built for real work
One tool. Three ways to see what matters.
Smart defaults adapt the same flexible heatmap workspace to reports, research, and exploratory analysis.
02
Academic Research
Calculate a Pearson correlation matrix automatically and export sharp SVG figures for papers and presentations.
03
Data Analysis
Pivot categorical data, inspect patterns and outliers, and tune the scale without writing chart code.
Three simple steps
From spreadsheet to insight in seconds
01
Add your data
Upload CSV or Excel, paste a table, or choose a sample. We recognize the structure automatically.
02
Customize the design
Pick a professional palette, tune the scale, refine labels, and see every change live.
03
Export and share
Download a crisp PNG for reports or an editable SVG for publications and design tools.
Everything you needClear heatmaps,
Clear heatmaps,
without the charting overhead.
Focused controls and thoughtful defaults help you produce a useful visual on the first try.
01
CSV and Excel support
Bring in `.csv`, `.xlsx`, or `.xls` files—or paste cells directly from the spreadsheet already open on your screen.
Automatic correlation matrices
Upload ordinary numeric columns and get a Pearson correlation heatmap instantly.
Professional color scales
Choose sequential, diverging, and color-blind-friendly palettes with precise limits and midpoint.
Publication-ready exports
Save high-resolution PNG for everyday use or editable SVG when every detail matters.
Private by design
Your data never leaves your browser.
Files are parsed and visualized on your device. We do not upload, store, or inspect your spreadsheet—because your data should stay yours.
- ✓No account required
- ✓No server-side file processing
- ✓No tracking of file names or values
Frequently asked questions
Everything you need to know
What data formats can I use?+
You can upload CSV, TSV, XLSX, or XLS files, paste tabular data from a spreadsheet, or start with one of three sample datasets.
Is my spreadsheet uploaded to a server?+
No. Your file is read and processed inside your browser. Its name, contents, and values are not sent to our servers.
Can the tool create a correlation matrix?+
Yes. When your table contains at least two numeric columns, the tool automatically calculates a Pearson correlation matrix.
What table structures are supported?+
The generator recognizes labeled matrices, three-column X/Y/Value tables, and ordinary datasets containing multiple numeric columns.
Can I use the exported heatmap in a paper or presentation?+
Yes. Export PNG at up to 3× resolution for slides and reports, or SVG for a sharp, editable figure suited to publication workflows.
Ready when you are
Create your heatmap →See the pattern hiding in your data.
No sign-up. No upload. Just a clear heatmap in a few clicks.