GrandPerspective deserves its place. It was the first tool on macOS to turn an opaque folder tree into a proportional treemap, it is open source under the GPL, and it is free with no nag screens. If your priority is seeing an honest map of your disk without paying, it is still a good answer.
What follows is a fair comparison, including the parts where GrandPerspective is the better choice.
What GrandPerspective does well
- It is open source. You can audit the code or build it yourself, and it will not be locked behind a licence.
- The map is honest. Each rectangle is proportional to real bytes, with no visual weighting.
- It is free. No trial, no feature split, no upsell.
- It is focused. It scans and draws. It does not try to be a system monitor or a cleaner.
Where it feels dated
- Navigation. Drilling into a folder means right clicking and choosing from a menu. Going back up means another menu. Modern analyzers let you click a block to zoom and use a breadcrumb to come back.
- Scan feedback on Apple Silicon. Scans of large trees can feel slower than the hardware suggests, because the scanning model predates NVMe speeds and multi core coordination.
- No cleanup. It finds the 41GB folder and stops there. Removing it is your problem, which is awkward when the folder is hidden inside
~/Library/Containers. - No context. A rectangle labelled
DerivedDatadoes not tell you that it is rebuildable, or that the 41GB next to it is a Docker disk image you should not delete casually. - No monitoring. Disk analysis cannot explain a slow Mac. Swap pressure and CPU saturation do not appear on a treemap.
What macoptimize does differently
macoptimize keeps the treemap and adds the parts that turn analysis into a result.
- Fluid navigation. Click to zoom, breadcrumb to go back, with the path always visible.
- Named developer caches. Xcode DerivedData, iOS DeviceSupport, simulator runtimes,
Docker.raw, node_modules, Gradle, npm and yarn stores are identified by path with their sizes and a plain explanation of what each one is. - Selection based cleanup. Nothing is deleted until you tick it. Docker volumes and archives stay unchecked by default because they are the risky ones.
- A history log. Every cleanup is recorded with a date and a size, so growth is visible instead of forgotten.
- Live monitoring. CPU per core, memory free, swap and disk sampled continuously with seven days of history, which is how you find out whether a slowdown is new or chronic.
- Local only. No account, no telemetry, dashboard served on
localhost:7777.
Cost over time
GrandPerspective is free forever, and that is a real advantage. macoptimize is $20 one time and covers 2 Macs, with free updates. Over three years that is roughly $6.70 per Mac per year, with no recurring charge.
If you want a free, read only map and you are comfortable deleting by hand in Terminal, GrandPerspective does that job well and you should keep using it.
If you want the map plus a monitor plus a cleaner that understands developer paths, macoptimize is a one time $20 for 2 Macs. See the details.
The test that settles it
Run both on the same disk and ask one question: after the scan, how many steps does it take to actually recover the space?
- With a read only visualizer: identify the folder, confirm it is safe by searching for the path, quit the app that owns it, delete it in Terminal, verify the space returned.
- With an analyzer that knows the path: select the category, confirm, watch the free space change, and read the entry in the log.
Both are valid workflows. They take different amounts of your time, and that is the real comparison.
Feature comparison, without the marketing
| Capability | GrandPerspective | macoptimize |
|---|---|---|
| Treemap of a folder | Yes, and excellent | Yes |
| Live CPU, memory, swap, disk | No | Yes, with history |
| Names developer caches as cleanable | No, it shows folders only | Yes, 19 locations |
| Deletes anything | No, viewing only | Yes, with confirmation and a log |
| Cost | Free, open source | $20 one time for 2 Macs |
| Runs as | Native app | CLI plus a local browser dashboard |
Where GrandPerspective is genuinely better
- Nothing to install. Download, open, pick a folder, look. No licence, no account, no first run setup.
- It is a specialist visualizer. For exploring an unfamiliar disk layout, its zoom and selection behaviour is refined after many years of work.
- It never deletes. If you want a tool that is structurally incapable of removing a file, this is that tool.
Where the workflow breaks
The gap is not visualisation, it is the step after it. A treemap answers "what is large" and stops. It does not tell you that DerivedData is rebuildable while Archives is not, that a Docker volume with data may matter while its build cache does not, or that a node_modules folder attached to a repo without a lockfile is worth keeping until you check. Those judgements are where the time goes, and they do not get faster with repetition.
Using both, which is the honest answer
They are not competitors so much as two halves of a workflow. A practical arrangement:
- Scan with macoptimize and read the categories it reports, each with a path and a size.
- Open GrandPerspective on a folder you are unsure about and look at it directly.
- Delete in the tool that keeps a record, so you can explain later where the space went.
That costs nothing extra, since the free tool stays free, and it gives you visual confirmation before any deletion.
The verdict
If your only question is where the space went, and you enjoy reading a treemap, GrandPerspective is enough and you should not spend anything. If your question is which of these folders you can delete safely and how the machine got here in the first place, a visualizer is where the work starts rather than where it ends. Twenty dollars once, for the half that names the folders and remembers what was removed, is the trade being offered.
FAQ
Is GrandPerspective still maintained?
Yes, it has been maintained steadily for many years by a single developer and it continues to work on current versions of macOS. For a free tool with that history, longevity is not really the concern.
Does macoptimize replace a visualizer completely?
For most cleanup decisions, yes. Its Analyze tab draws a treemap of your home folder sized by real bytes, and the Clean tab groups findings into named categories. A dedicated visualizer still gives you finer control when you want to explore a specific folder in depth.
Can I use the free tool to verify what macoptimize will delete?
That is a good use of it. Scan a folder, read the size macoptimize reports, then open the same folder in the visualizer and compare. Two independent measurements agreeing is the most useful confirmation you can get before deleting anything large.
Which one should I install first?
If you are unsure, start with the free visualizer and see whether the information it gives you is enough to act on. If you find yourself repeatedly looking at folders and not knowing whether they are safe to remove, that is the signal that the paid tool answers a question you actually have.