WizTree vs TreeSize Free: Which Disk Space Tool I Kept on the Office PC

We kept WizTree and uninstalled TreeSize Free. The reason is boring and practical: WizTree pulls its data straight off the NTFS Master File Table rather than walking the directory tree one item at a time, so a scan that TreeSize takes minutes to grind through finishes in about a second.

That matters more than it sounds when you are the person who also does the books, answers the phone, and occasionally has to find out why the invoicing PC is out of disk space on a Tuesday morning.

Here is how the two actually compare on a small office machine, and where TreeSize still makes sense.

Why the speed gap is bigger than the spec sheet suggests

WizTree gets its speed from the same trick the Everything search tool uses. It reads the MFT, the index NTFS keeps of every file on the volume, rather than walking the directory tree the way a conventional disk analyzer does. On a drive with around 300,000 files, a full scan ran in under a second and a half, and the tool shows you the timer when it finishes. We are not exaggerating when we say it feels instant.

TreeSize Free walks the file system. On a lightly used laptop that is fine. On the machine holding three years of scanned invoices, a shared accounts folder, and a stray Windows.old from a botched update, that crawl takes long enough that you go and make coffee. We timed it once, got bored, and stopped bothering.

If you only run a scan twice a year, the difference is academic. If you run one every time Windows starts complaining, it changes how often you actually clean up. That is the real benefit.

What the treemap does that Settings cannot

Windows 11’s Storage page will tell you that temporary files are eating 14 GB. It will not tell you which folder. That is the exact gap these tools fill.

WizTree paints everything as colour-coded blocks sized to how much space each item uses. A forgotten 8 GB video file is a giant rectangle you cannot miss. We found a recording of a supplier demo from two years ago that way, sitting on the desktop of all places, and deleted it in about four seconds. It also scans exFAT and FAT32 volumes, network drives, and MTP devices such as phones and cameras, so the same interface works when someone hands you a USB stick to sort out.

TreeSize Free has a treemap too, and its column view, sorted by size with percentages, is genuinely tidy. Both tools let you right-click an item and open its location, copy the path, or delete it without jumping to File Explorer. Neither one protects you from yourself.

The part nobody warns you about

Both programs will happily show you a huge Windows folder that looks like obvious junk. It is often not. System files, application data, and program folders sit there looking fat and deletable, and removing the wrong one breaks something that takes an afternoon to fix.

Our rule is simple. We only delete files we recognise as ours, plus the standard safe targets: old downloads, duplicate exports, video files, and anything in a folder with a client name on it. If a big block sits inside Windows or ProgramData, we leave it alone and let Disk Cleanup handle it. The treemap tells you where the weight is. It does not tell you what is safe.

Pricing and licensing, plainly

Both have a free tier, and for a two-person shop that is usually the whole story. WizTree is published by Antibody Software and runs on Windows. The free version covers scanning and the treemap. A business licence exists for companies that need to use it commercially under clear terms, which is worth checking if you are running it on a work machine rather than a personal one. We bought it, mainly because the tool saves us enough time each quarter that the cost is a rounding error against an hour of our own.

TreeSize Free is also free for personal and, with some conditions, commercial use. Read the licence before you roll it out across a team.

Where TreeSize Free is the better pick

Two situations, honestly.

The first is if you work mostly on network shares or non-Windows storage where the MFT trick does not apply. The speed advantage shrinks, and TreeSize’s steady, thorough crawl is fine.

The second is if you prefer a dense list of folders sorted by size over a visual map. Some people find treemaps pretty but hard to read. TreeSize’s columns are easier to skim when you want a number, not a colour.

If neither applies, WizTree is the one we would install first.

How we actually use it in the office

We run a scan on the accounts PC at the end of each month, before the backup, mostly to catch anything bloated that snuck in. It takes a minute including the decision about what to delete. We also scan any USB drive a client hands us before copying files off it, because you never know what is on there.

The habit that saves the most space is not the tool at all. It is deleting our own exports after we have sent them. A scan just makes that obvious.

WizTree is the one that stayed installed. It is faster, it shows us the drive in a way that makes the biggest problems impossible to ignore, and it does not get in the way. TreeSize Free is a capable backup option if you ever need one, and nothing more than that.