Which fits your needs?
GrandPerspective: People who want a free, inspectable treemap and reusable scan records.
NullDisk: Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports.
Features, pricing, and workflow
Scroll across to compare
| Feature | GrandPerspective | NullDisk |
|---|---|---|
| Best fit | People who want a free, inspectable treemap and reusable scan records. | Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports. |
| Visualization | Treemap with configurable colors and filters | Radial map, treemap, and file list; CLI terminal treemap |
| Platforms and requirements | macOS 14+ (current release) | Mac app: macOS 14+; CLI: macOS, Linux, Windows |
| Pricing and editions | Free from SourceForge; the same app is $2.99 in the US App Store. | Direct Mac edition free with reminders; optional $9.99 one-time personal license or team seat removes reminders. App Store terms are separate. |
| Open source | Yes | No |
| Native macOS UI | Yes | Yes |
| Cleanup workflow | Delete files or folders from the view; review selection and deletion preferences. | Review source and action: local Trash, explicit permanent removal, or backup/delete; remote and cloud actions depend on the destination. |
| Reports and portability | Save the scan for reopening in GrandPerspective, or export text and images. NullDisk does not import GrandPerspective scan files; retain exports and rescan the same location. | CLI produces JSON/NDJSON scan reports. Third-party scan files are not directly imported into the Mac GUI. |
GrandPerspective: what stands out
A good fit for people who want a free, inspectable treemap and reusable scan records.
GrandPerspective: strengths
- Configurable colors, masks, searches, and scan exclusions
- Quick Look, Finder integration, and file/folder deletion
- Save/reload scans and export text or images
Considerations
- Treemap rather than radial navigation
- Older macOS versions require an older release
- App Store updates can follow SourceForge releases later
NullDisk: what stands out
A good fit for Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports.
NullDisk: strengths
- Radial and treemap views with local, SSH, and cloud sources
- Git-aware development cleanup for generated output and eligible worktrees
- Native Mac UI plus terminal UI and JSON/NDJSON CLI reports
Considerations
- Desktop GUI requires macOS 14+; Linux/Windows use the separate CLI
- Mac app sends anonymous usage telemetry; no in-app opt-out at this review
- No content-based duplicate finder; allocated bytes are not a guaranteed recovery total
For a useful comparison on your own drive, match the scan root, access permissions, and size mode. Chart style changes how you explore the results; it does not by itself establish measurement accuracy.
Common questions
When should I choose GrandPerspective?
A good fit for people who want a free, inspectable treemap and reusable scan records. Free from SourceForge; the same app is $2.99 in the US App Store.
When should I choose NullDisk?
A good fit for Mac users managing local/remote storage, and developers who need Git-aware cleanup or scriptable disk reports. Direct Mac edition free with reminders; optional $9.99 one-time personal license or team seat removes reminders. App Store terms are separate.
Will both apps show the same size?
Not necessarily. Match the scan root, permissions, exclusions, and logical/allocated-size mode. Hard links, APFS clones, snapshots, sparse files, and cloud placeholders can change totals. A reported size is not a guaranteed amount recovered after deletion.