Excel Heatmap Viewer
Upload an Excel or CSV file and visualize numeric data as a compact heatmap. Spot patterns at a glance.
Drag & drop an image here
or click to select a file
.xlsx, .xls, .csv
All processing happens in your browser. Files are never uploaded to any server.
💡 Hover over the heatmap to see row, column, and value. Click to open a zoom window showing nearby cells with actual values.
Heatmap will appear here
Tips for Effective Heatmaps
Prepare Your Data
For best results, use a table of purely numeric values. Non-numeric cells are treated as empty. Column headers in the first row are fine.
Adjust Cell Size
Shrink cell width and height to see the full dataset at a glance. Enlarge them when you need to inspect specific regions more closely.
Choose a Color Scheme
Try different schemes to highlight what matters. Blue and Green are good for general data; Heat and Viridis emphasize extremes more dramatically.
Export as PNG
Download the heatmap as an image to include in reports, presentations, or documentation. The exported image matches exactly what you see on screen.
Common Use Cases
Visualize monthly or regional sales figures to quickly spot top performers and underperformers.
Display temperature readings, pressure measurements, or experimental results across time and location.
Map page views, bounce rates, or conversion metrics by day and hour to find engagement patterns.
Monitor production line metrics to detect defects, deviations, or batch-level anomalies.
Scan large financial spreadsheets for outliers, trends, or suspicious values at a glance.
Present survey results, correlation matrices, or experimental data in a compact visual format.
Frequently Asked Questions
Is my file uploaded to a server?
No. All processing happens entirely in your browser. Your files never leave your device.
What file formats are supported?
You can upload Excel files (.xlsx, .xls) and CSV files. Multi-sheet Excel workbooks are supported — use the sheet selector to switch between them.
How large can the spreadsheet be?
There is no strict row or column limit. However, very large files (hundreds of thousands of cells) may take longer to render depending on your device. Shrinking cell size helps display large datasets.
What happens to non-numeric cells?
Text, dates, and empty cells are treated as blank and displayed in a neutral color. Only numeric values are mapped to the color scale.
Can I customize the value range?
Yes. Turn off Auto Range and set your own Min and Max values. This is useful when you want to compare multiple sheets or files on the same scale.
Can I use the exported heatmap image commercially?
This tool imposes no restrictions on the exported image. However, if the underlying data is confidential or proprietary, please ensure you have the appropriate permissions before sharing or publishing the heatmap.