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Turn any CSV into a treemap.

Size rectangles by a number and nest them by group and subgroup. The biggest contributors take up the most space — composition you can read in one glance.

01 · How it works

Three steps, then done.

A treemap shows part-to-whole composition: each rectangle's area is its share of the total. Pick a group column, an optional subgroup for nesting, and the numeric column that sets each rectangle's size.

i. drop

Drop your CSV

Delimiters and column types are detected automatically; Excel files convert on the fly.

ii. nest

Pick group, subgroup, size

Group by one category, optionally nest by a second, and size by any numeric column (or row count).

iii. see it

See what dominates

The biggest blocks are your biggest contributors. Hover for exact values, then export SVG or PNG.

02 · Why ours

Composition at a glance.

Pie charts die after five slices. A treemap shows dozens of parts and their hierarchy at once.

  • 01

    Squarified layout

    Rectangles are kept close to square so areas are easy to compare — not the skinny slivers naive treemaps produce.

  • 02

    Two-level nesting

    Group and subgroup nest visually with labelled borders, so hierarchy is obvious.

  • 03

    Area = value

    Each rectangle's area is exactly proportional to its share of the total. What's big is big.

  • 04

    Export ready

    Download as vector SVG or 2× PNG for slides and reports.

"Three categories were 80% of spend. Obvious in the treemap."
— every budget review
03 · FAQ

treemap questions.

What columns do I need?
One category column to group by and one numeric column for size. A second category (subgroup) is optional and adds nesting. Without a numeric column we size by row count.
We lay out the top groups and their sub-items, capping the count so labels stay legible. Tiny slivers are still drawn, just unlabelled.
Yes — Download SVG or Download PNG (2× resolution).
No. The treemap is computed locally.