Skip to content

How to read the treemap

This guide is for MacDirStat users who have already run a scan and want to understand what the chart is showing them.

Understand what an arc represents

Each arc in the ring is one file or folder. Two things about an arc carry information:

  • Angle. A wider arc holds more disk space. Angle is proportional to size within its parent, not to the whole disk.
  • Radius (distance from center). Deeper arcs sit farther from the center. A file three folders deep sits in the third ring band out.

Understand the default colors ("By Type")

By default, MacDirStat colors files by category, not by individual extension:

Color Category Example extensions
Orange Video mp4, mov, mkv
Emerald Images jpg, png, heic
Cyan Audio mp3, wav, flac
Blue Code swift, py, js
Violet Documents pdf, docx, md
Red Archives zip, dmg, pkg
Yellow Data / config json, yaml, sqlite
Teal Web html, css
Pink Fonts ttf, otf, woff
Lime 3D / models obj, fbx, gltf

An extension MacDirStat does not recognize gets a stable color derived from its name, so the same unknown extension is always the same color across a scan. Folders are colored separately from files: each folder gets a muted, low-saturation tint based on its name, so folders never compete visually with the files inside them. Files also darken slightly with depth, so you can tell a top-level file from one buried five folders down at a glance.

Change the color scheme or size units

  1. Click the gear icon (Settings & About) in the dashboard.
  2. Under Appearance:
  3. Color scheme: choose By Type (default), Rainbow (one hue per extension, no category grouping), or Mono (grayscale, useful for spotting size outliers without color as a distraction).
  4. File size units: choose Decimal (KB/MB/GB, 1000-based) or Binary (KiB/MiB/GiB, 1024-based).

Zoom in and out

  • Click an arc that represents a folder to make it the new center ring.
  • Click the center circle to zoom back out one level.

See also