GrandPerspective is a free Mac utility that maps your disk space as a colour-coded treemap, turning an abstract storage problem into an instantly readable picture of which files are eating your drive.
What is GrandPerspective?
GrandPerspective is a native macOS disk-usage visualiser that renders every file on a chosen volume or folder as a filled rectangle, with area directly proportional to file size. The result is a zoomable mosaic — a treemap — where the biggest space-hogs announce themselves immediately as the largest coloured blocks on screen, no hunting through Finder columns required.
The app has been maintained by indie developer Erwin Bonsma for well over a decade. It is free to download, open-source, and quietly beloved by Mac power-users who need to answer one question quickly: where did all my storage go?
What does GrandPerspective do best?
Its single superpower is turning an incomprehensible directory tree into a glanceable visual map. I use it every few months on my main working volume, and every time it unearths something embarrassing — a forgotten Xcode device support folder consuming 8 GB, a 4 K export I rendered last year and never deleted, a VM snapshot I meant to trim six months ago.
- Instant visual triage: the largest rectangles are literally the largest files; you spot them in under two seconds.
- Colour-coded by folder: each top-level directory gets a distinct hue, so you can see at a glance whether your clutter lives in Movies, Developer, or a buried Library cache.
- Click-to-reveal: clicking any rectangle shows the full path in the info bar and lets you open the file or its enclosing folder directly from the app.
- Filter and zoom: you can restrict the scan to a subfolder, set a minimum file-size threshold to filter out noise, and zoom into any region to drill down.
- Fast scanning: even on a full-capacity SSD with hundreds of thousands of files, scans finish in seconds on Apple Silicon.
Where it purposefully does not compete: GrandPerspective will not delete files for you, move anything, or make automated recommendations. That restraint is a feature — it keeps the app simple, safe, and auditable. You decide what goes; GrandPerspective just shows you the map.
Is GrandPerspective free?
Yes — GrandPerspective is completely free to download and use, with no trial limits, nag screens, or premium tier. The source code is publicly available under an open licence, hosted on SourceForge. If you want to support Erwin's work there is a donation option, but nothing is gated behind it.
Who should use GrandPerspective?
Anyone on a Mac who has ever looked at a nearly-full disk and thought "I have no idea what's in here" will benefit immediately. That said, GrandPerspective earns its place in a power-user toolkit specifically because it is unmediated — it does not oversimplify. Developers will recognise duplicate build artefacts and forgotten Docker layers; photographers will spot a burst of RAW files from a shoot they culled months ago; video editors will find oversized proxy caches. If you mostly live in documents and browser tabs, the built-in macOS Storage Management panel in System Settings may be sufficient.
What are the best GrandPerspective alternatives?
The closest native competitor is DaisyDisk, which offers a more polished, animated sunburst visualisation and a built-in deletion flow — but costs around $10. OmniDiskSweeper takes a list-based approach (sorted by size, folder by folder) and is free, but lacks any visual map. On the command line, ncdu or dust serve developers who never leave the terminal. GrandPerspective sits in a sweet spot: treemap clarity without the price tag, and without the hand-holding that DaisyDisk adds for mainstream users.
How does GrandPerspective compare to DaisyDisk?
DaisyDisk wins on aesthetics and workflow integration — its sunburst chart is beautiful, and you can drop files into a "collection" to preview and bulk-delete in one pass. GrandPerspective wins on cost (free vs paid), data density (treemaps show more files simultaneously than sunbursts), and scanning scope (it handles edge-case paths and package internals that DaisyDisk sometimes smooths over). I keep both installed: GrandPerspective for quick audits and raw exploration, DaisyDisk when I want to act and need a guided deletion flow. If you will only install one, GrandPerspective is the one that costs nothing and surprises you every time.
