Every free way to find what is using your Mac's disk, compared
Six free options, what each is actually good at, and the one question none of them answers. Checked prices and versions as of September 2026.
There are more free ways to answer this question than people realise, and the differences between them are real. This is all of them, with what each is genuinely best at, checked in September 2026.
The options
| Tool | Cost | Shape | Best for |
|---|---|---|---|
| System Settings, Storage | Built in | Categories | Old device backups and large apps |
du in Terminal | Built in | Text list | One command, no install, hidden folders included |
| GrandPerspective | Free, or $2.99 | Treemap | Seeing the whole drive at once |
| OmniDiskSweeper | No price named | Sorted list | Exact numbers, no graphics |
| ncdu | Free via Homebrew | Interactive text | Drilling down without rescanning |
| Free Mac | Free to scan | Treemap plus app and developer views | Knowing what a large folder belongs to |
Start with the two that are already installed
The storage screen in System Settings finds old iPhone backups and large applications faster than anything else, because it knows what they are. It cannot show folders and will not open System Data, which is where it stops.
du -xh -d 1 ~ 2>/dev/null | sort -h | tail -20That one line covers most of what any of these tools do, including the hidden folders Finder will not show you. If it ends with a folder you cannot explain, that is your answer and you did not install anything.
When a graphical tool is worth it
Three situations, honestly:
- You want to see proportion rather than read numbers. A treemap does that instantly and a list does not. GrandPerspective is free and still actively released.
- You want to drill in repeatedly. ncdu in a terminal, or any graphical tool, beats running du five times.
- You do not know what the folder is. This is the one none of the pure measuring tools solve.
The question none of them answer
Every tool above will tell you that a folder is 6 GB. None of them will tell you that it belongs to an app you uninstalled two years ago, or that it is a cache that will be back next week, or that it is the only copy of something. That distinction is what makes the difference between finding space and safely reclaiming it.
It is also why the guides on this site are organised by what the folder is rather than by how large it is: what uninstalling leaves behind, what is in your Library folder, and the order to free 100 GB safely.
If you would rather pay
The paid one time options are worth knowing about because they age well: DaisyDisk at $9.99 and WhatSize at $14.99, both checked in September 2026. The subscription suites are a different proposition, covered in the CleanMyMac comparison and the MacKeeper one.
Common questions
What is the best free disk space analyzer for Mac?
GrandPerspective if you want a treemap and active releases, ncdu if you are comfortable in a terminal, and the built in storage screen if your problem is old device backups or large applications. For one large file, du needs no installation at all.
Does macOS come with a disk analyzer?
It comes with a storage screen that sorts your disk into categories and lists applications and iOS backups by size, and with du in Terminal. Neither shows folders in a browsable way, which is what people usually mean by an analyzer.
Do I need to pay for a Mac storage tool?
Not to find what is large. Free options cover that completely. Paying is worth considering when you want a polished interface, or when you want a tool that identifies what a folder belongs to rather than only how big it is.
Are free Mac cleaner apps safe?
Measuring tools are low risk, since they only read. Be more careful with anything that offers to clean automatically, particularly if it cannot explain what a file is. Prefer tools that move files to the Trash and show you the list before acting.