Disk & Storage Guide
By WizTree reads the NTFS file table straight off the disk, so a full drive finishes in seconds and it wins on raw speed. WinDirStat walks the folder tree and is open source, so it stays free on any PC including work machines. Both draw a treemap and can export a CSV. Choose WizTree when speed is all you want. Choose WinDirStat when the machine is not yours to license. Choose a reporting tool when you must hand the result to someone else.
You want to see what is filling a drive and two names keep coming up: WizTree and WinDirStat. They do the same job in different ways, and the right pick depends on one or two things you care about most. This guide lays them next to each other in plain terms.
At the end it shows where Univik Disk Usage Reporter sits, because on a work or client PC the missing piece is often a report you can share and a vendor to call, not another scanner.
WizTree vs WinDirStat: Which Is Faster?
WizTree is faster, and the gap is wide on a big drive. It pulls the file records from the NTFS table in one go rather than opening each folder in turn, and that shortcut is what gets a full disk done in a few seconds. The catch is that the table read is a low-level operation, so Windows only allows it with admin rights and WizTree prompts for them when it opens.
WinDirStat takes the ordinary route. It reads the folder tree the way Windows does, counting each file as it goes. That is slower on a drive with millions of files, but it needs no special rights and shows a live count while it works. On a small drive you will barely notice the gap.
WizTree vs WinDirStat: Which Is Free for Work?
This is the deciding point for a lot of people. WinDirStat is open source and costs nothing on any machine, a company laptop included, with no licence to buy. WizTree only gives its free licence to home and personal users. Put it on a business machine and Antibody Software expects you to buy a commercial licence.
So if you are on a work machine and want to spend nothing, WinDirStat is the safe choice. If you are at home and want the quickest scan, WizTree is fine and free. Neither is a trick. They only draw the free line in different places.
WizTree vs WinDirStat vs Univik at a Glance
Here is how the two popular tools line up, with Univik Disk Usage Reporter added as a third option so you can see the reporting angle too.
| What matters | WizTree | WinDirStat | Univik Disk Usage Reporter |
|---|---|---|---|
| Scan speed | Fastest of the three | Slower on large drives | Fast parallel scan |
| How the scan works | Reads the NTFS file table, needs admin | Walks the whole folder tree | Multi-threaded folder read |
| Treemap view | Yes | Yes | Yes, zoomable |
| Largest files with full path | Yes | Through the tree view | Yes, on one screen |
| File type summary | Yes | Yes, by extension | Yes |
| Duplicate finder | No | Yes, in version 2 | Planned for Pro |
| Report you can share | CSV only | CSV only | HTML and CSV |
| Cost for business use | Paid licence needed | Free, open source | Free, with optional Pro |
| Help when you are stuck | Community | Community | Email and live chat |
| Best fit | Quick scans at home | A free tool for any PC | A report with support |
The pattern is clear. WizTree owns speed and WinDirStat owns the free-anywhere licence. Univik is the one built around a report you can share and a team to ask when a scan looks wrong.
What Each Disk Space Analyzer Does Best
WizTree is the tool to grab when you only want a fast answer on your own PC. The direct table read makes it the quickest of the three. The treemap and file list are clean, and home use costs nothing. Its weak spots are the business licence and the lack of a built-in report.
WinDirStat is the pick when the machine is not yours to license. It is open source and free on any PC. Version 2 even added a duplicate finder that the others do not match. It is the slowest of the three on a huge drive and its look is plainer, but the price and freedom are hard to beat.
Univik Disk Usage Reporter is the one to reach for when the scan is only half the task and you need to show the result to someone. It reads folder sizes, draws a treemap and lists the biggest files, then saves an HTML or CSV report. It is free with an optional Pro, and it comes with real support.
When to Choose Univik Disk Usage Reporter
Both popular tools are good at showing space on screen. What they leave out is the part after the scan. On a work or client drive you often have to prove what was eating the space, or send a tidy summary to IT. That is the job Univik Disk Usage Reporter is built for.
It runs a quick parallel scan, then puts everything on one screen: which folders hold the most, a treemap you can click into, the largest files with their exact location and a breakdown by file type. When you are done, the Export menu writes it up as an HTML report you open in a browser or print, or a CSV for Excel. It all runs locally and sends nothing out. If you want that plus email and live-chat support, it is worth a try.
People do not really want a scanner, they want to know what to delete and be able to prove it later. That is why we put the report and the support front and centre instead of chasing WizTree on raw speed.
Univik Disk Usage Reporter maps a drive into folders by size, a treemap and a largest-files list, then writes the result to an HTML or CSV report you can pass on. Free to start, no account.
Windows 7 to 11 · no sign-up · runs offline on your PC
The short version
- WizTree wins on speed thanks to its direct NTFS table read, and it stays free at home.
- WinDirStat is open source and free on any PC, and its version 2 has a duplicate finder.
- WizTree needs a paid licence for business use, WinDirStat does not.
- Both export CSV only. Neither builds a ready-to-read report.
- Univik Disk Usage Reporter adds an HTML report, one-screen views and support, free to start.
Try Univik Disk Usage Reporter free
WizTree and WinDirStat Questions
About This GuideThe Univik team put this comparison together, with Leena Taylor Paul as the named editor. Univik has built Windows file and disk tools since 2013. We rechecked the speed, price and feature claims on all three product sites this September. Reviewed 22 September 2026. Still weighing up a choice? Reach the team from the button above.
Sources we checked: WizTree by Antibody Software · WinDirStat project · the Univik Disk Usage Reporter page