Online Tool Store
Treemap Maker
Turn labelled values into nested rectangles where area shows magnitude, with category grouping, colors, and readable labels.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Data & CSV
Treemap Maker
Frontend preview — no upload or external service.
Treemap preview
A household budget of 3,200: Housing takes 45% of the area, Food 18%, Transport 12%, and eleven smaller items share the remainder.
How the Treemap Maker works
- Enter one label and value per line, optionally with a category to group by.
- Choose whether colour carries category or magnitude — using it for both makes the chart unreadable.
- Check the smallest rectangles still show a label; if not, group the tail into an "Other" item.
The method
A treemap allocates area in proportion to value, subdividing the canvas so each rectangle's share of the total area equals its share of the total value.
rectangle area = (value / total) x canvas area
Housing at 1,450 of a 3,200 total occupies 45% of the canvas, regardless of the shape it is squeezed into.
FAQ
When is a treemap better than a bar chart?
When you have many items and care about share of a whole more than exact comparison. Bars are more precise; treemaps handle fifty categories without becoming a wall of ticks.
Why are treemap comparisons hard to read?
Because people judge length far better than area, and rectangles of different aspect ratios read as different sizes even when equal. Keep values labelled rather than relying on the eye.
What about negative values?
They have no meaning in an area chart. Split them into a separate view rather than trying to represent them here.
How we compare
| Feature | Online Tool Store | A spreadsheet | A BI platform |
|---|---|---|---|
| Handles many categories | ✓ | Cluttered | Yes |
| Grouping into parent blocks | ✓ | ✗ | ✓ |
| Values labelled on tiles | ✓ | Manual | ✓ |
| No account or upload | ✓ | ✓ | ✗ |
Treemap Maker is for share-of-whole with a long tail — and it labels values, because area alone is the weakest comparison the eye can make.