GrandPerspective
Pros
- Treemap view makes large files instantly obvious
- Tiny download, native macOS app
- Free and open source
- Filters by file type, size, and age
Cons
- macOS only
- UI is functional, not pretty
- First scan of a full drive can take a few minutes
I decided to buy it via AppStore to support devs, but there is an option to download it for free.
GrandPerspective is one of those small apps that solves one problem very well. It scans a folder or drive and shows a treemap, where every rectangle is a file. The bigger the rectangle, the bigger the file. In one screen, you can spot what is eating your disk.
The biggest value is speed of diagnosis. Instead of opening many folders manually, you can run a scan and instantly notice heavy areas like old backups, large video exports, or cache directories. I have used it to find forgotten build artifacts and old archives in minutes.
It is important to know what it does and what it does not do. GrandPerspective helps you see storage usage clearly, but it is not an automatic cleaner. You still delete files yourself in Finder (or Terminal), which is actually good when you want full control.