WinDirStat
WinDirStat is one of the older names in this space, known for its treemap view: a colored mosaic where each tile is a file and area corresponds to size. It fits a user who wants a quick, visual answer — 'what is this one giant blob in the corner' — over a detailed tabular report.
It's distributed as open-source software, which means the source code is publicly available and community-maintained rather than backed by a commercial support team. That makes it a common default recommendation for people who specifically want an open-source tool, though update frequency for community projects can vary.
WizTree
WizTree's defining feature is scan speed on NTFS volumes: it reads the Master File Table directly instead of walking the folder tree file by file, which makes large local drives scan noticeably faster than tools using a conventional directory walk. It fits someone who scans the same large drive repeatedly and wants results in seconds.
It presents results as a sortable folder list alongside a treemap view, similar in spirit to other tools here. Licensing is freeware for personal use, with a separate paid tier aimed at business or commercial use — check the developer's current terms for your specific situation before deploying it at work.
SpaceSniffer
SpaceSniffer leans further into the visual, exploratory side than the others: its treemap-style view lets you zoom, filter by pattern, and drill in interactively rather than reading a ranked list. It suits someone who wants to poke around a drive's structure visually rather than run a fixed report.
It's distributed as freeware and runs without a formal installer, which also makes it convenient to run from a USB stick on a machine you don't want to install anything on.
Windows' built-in Storage settings
Settings > System > Storage on Windows 11 and Windows 10 is not a third-party tool, but it's the option that requires installing nothing at all. It breaks disk usage down into broad categories — apps, documents, temporary files, system — and includes a cleanup recommendation feature for removing temp files and old Windows update leftovers.
It fits someone who wants a rough, low-effort answer and is comfortable with Microsoft's categories rather than a full folder-by-folder tree. It doesn't offer a treemap or a sortable list of individual folders, which is the main thing a dedicated analyzer adds on top. Our comparison of Windows Storage settings against TreeSize goes through this gap in more detail, and the general mechanics behind any of these tools are covered on the Windows disk space analyzer guide.
TreeSize
TreeSize presents results as a sortable folder tree with percentage-of-parent columns, plus optional pie-chart and treemap views, and it can scan local drives, network shares, and (in its paid editions) generate scheduled reports. It fits both a one-off home cleanup and repeatable administrative reporting, depending on which edition is in use.
It's published in a free edition for personal use and paid editions — Professional and higher — that add scheduling, duplicate-file search and reporting aimed at IT administrators. The free-versus-paid line is covered in detail on TreeSize Free vs. Professional.
Side-by-side comparison
| Tool | Presentation style | Scan approach | Typical use | Licensing model |
|---|---|---|---|---|
| WinDirStat | Colored treemap plus folder list | Standard directory walk | One-off visual cleanup, open-source preference | Open source |
| WizTree | Folder list plus treemap | Reads the NTFS Master File Table directly for speed | Repeated scans of large local drives | Freeware (personal); paid tier for business use |
| SpaceSniffer | Interactive zoomable treemap | Standard directory walk | Exploratory, no-install browsing of a drive's structure | Freeware |
| Windows Storage settings | Category bars, no folder tree | Built into Windows, no separate scan step | Quick, low-effort overview without installing anything | Built into Windows |
| TreeSize | Sortable folder tree, pie chart, treemap | Standard directory walk, with network/share support | Home cleanup through recurring administrative reporting | Free edition plus paid editions (Professional and higher) |
This table compares stated characteristics only. It isn't a ranking, and the right tool for you depends on which column matters most — scan speed, visual style, licensing, or reporting depth.
How to actually choose
Start from your own criteria rather than a general recommendation. If you scan the same large NTFS drive often, scan speed probably matters most. If you manage several machines and need a repeatable report, scheduling and export options matter more than raw speed. If you just want to see what's eating space on one home PC today, almost any of these will answer that question adequately.
Whichever tool you land on, the concepts are shared across all of them — see the Windows disk space analyzer guide for what a treemap actually encodes and how logical size differs from allocated space. And regardless of which analyzer flags a folder, use the same judgment before deleting anything; our guide to finding large files on Windows covers that decision separately from the scanning tool itself.
Frequently asked questions
Is WinDirStat as accurate as TreeSize?
Both read the same underlying file system data, so their raw size figures should be comparable. Differences you see are usually about which size mode (logical vs. allocated) each is displaying, not accuracy.
Which of these tools is fastest on a large drive?
Can I use the Windows built-in Storage view instead of installing anything?
Do any of these tools work on network shares?
Is open-source software safer than freeware for this kind of tool?
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