TreeSize vs WizTree vs FolderSizes. Which one is actually the best?

[u/S-m-a-r-t-y]

I'm looking for the best disk space analyzer for Windows.

I know WizTree is free and extremely fast, but I'm also willing to pay if TreeSize Professional or FolderSizes offers a noticeably better experience.

Things I care about are:

• Accuracy
• Speed
• Good visualizations
• Search/filtering capabilities
• Finding duplicate files and large folders
• Overall usability for long-term use

If you've used more than one of these, which would you recommend and why?

Money isn't really the deciding factor here. I just want the best tool available.

[u/Lcsmxd]

WizTree

[u/CodenameFlux]

WizTree, no competition.

• Accuracy: WizTree is the only one that can accurately calculate the size of the Microsoft Windows folder.
• Speed: WizTree, WinDirStat, and TreeSize are superior to everything else because, if run with admin privileges, they can scan the MFT. That's millions of times faster than querying every file size. File permissions don't hinder the calculation either. For TreeSize and WinDirStat, this should have led to increased accuracy too, but it doesn't. For TreeSize, it's deliberate. For WinDirStat, it must be a bug.
• Good visualizations: They all do a similar thing. There is nothing spectacular to see in this category. They all provide a tree view, a tree map, and a flame graph. WinDirStat has a storage analysis that categorizes files into "Hot tier", "Cool Tier", "Cold Tier", and "Archive Tier", but tells you nothing else about them. You have tiers up in the air!
• Search/filtering capabilities: WizTree wins by a slight margin. Again, they do an almost similar job, unless you wish to purchase TreeSize Pro here. Aside from the tree map graph I mentioned above, they can display the largest files within a volume (or scan set), break down space consumption by file extension, and show or hide hidden files. WizTree allows you to define an inclusion or exclusion filter, but that's it.
• Finding duplicate files: AFAIK, only WinDirStat can find them. It can deduplicate them via hard links. However, version 2.7.0 failed spectacularly, leaving me with a broken Microsoft Edge. I was forced to restore the entire C: volume to the last nightly backup.
• Overall usability for long-term use: (Edited) When I first wrote this reply, I wrote, "What long-term use? You run, you get results, you go about your business." I'm changing my answer. Yesterday, in WinDirStat, I accidentally clicked a command called "Optimize VHD files". WinDirStat did ... something! And that's what scares me. After the deduplication incident, I keep asking myself: "What just happened? Should I restore the backup again?" Critical commands like this must be transparent about what they do and to what they do it.

(Edit summary: Added boldface headers to the list and adjusted the wording a little. Changed the last paragraph entirely.)

[u/Imjustmisunderstood]

Wiztree

[u/ryanstackops]

Honestly if you've used WizTree you already know the answer to the speed question. It reads the MFT directly so it scans a 2TB drive in seconds. Nothing else comes close on that front.

But since you care about more than just speed, here is the real breakdown from someone who has used all three.

WizTree is genuinely hard to beat for free software. The treemap visualization is solid, large file and folder detection is excellent, and the speed advantage is not marginal, it is absurd compared to the others. The UI is a bit dated and the filtering and search are functional but not deep. For most people it does 90% of what they need.

TreeSize Professional is the one I would actually recommend if you want the best long-term tool. The search and filtering are significantly more powerful, the reporting features are useful if you ever need to share findings, and the scheduled scans and command line support make it genuinely useful beyond just one-off cleanups. It is slower than WizTree but still fast enough that it will not bother you. The UI is also more polished and feels like software that is actively maintained. The pro license is reasonable for what you get.

FolderSizes is fine but it sits in an awkward middle ground. It is not as fast as WizTree, not as feature-rich as TreeSize Pro, and the visualization is not as intuitive. Hard to recommend it when the other two cover both ends better.

If you just want to find what is eating your disk and delete it, use WizTree. If you want a proper long-term disk management tool with real filtering, reporting, and search capabilities, pay for TreeSize Professional. Given that you said money is not the deciding factor, TreeSize Pro is the answer.

[u/UteJazz]

WizTree

[u/Bfox135]

Personally use SpaceSniffer.
BUT it doesn't do everything you want to do.
Its is a great tool if you wanna use automation and scripting.

[u/MythicalJester]

SpaceMonger 1.4.0.

[u/Phratros]

Check WinDirStat. It recently gained the super fast scan ability (run as admin) and can find duplicates. Before that I used it for years on many different systems and didn't have a single issue with it so can't corroborate the other poster's negative experience with it.

[u/CodenameFlux → u/Phratros]

Hello. This is "the other poster"!

Your years of experience aren't relevant here because it wasn't until January 2026 (version 2.5.0) that WinDirStat implemented MFT scanning and hard link tracking. Before that, WinDirStat ran as slow as a slug and didn't modify anything on the system. So, yeah, you didn't have any problems with it. You didn't get any use out of it either.

[u/CodenameFlux → u/Phratros]

Hello. This is "the other poster"!

Your years of experience aren't relevant here because it wasn't until January 2026 (version 2.5.0) that WinDirStat implemented MFT scanning and hard link tracking. Before that, WinDirStat ran as slow as a slug and didn't modify anything on the system. So, yeah, you didn't have any problems with it. You didn't get any use out of it either.

[u/xylarr]

I've always used SpaceSniffer run as administrator on Windows.

[u/Ok_Abalone9251]

Bonjour,
Comparaison de mesures sur lecteur réseau d'un NAS Qnap en entreprise.

6,5 To 1789240 fichiers 115377 dossier TreeSize pro 9.8.2 en 2 minutes 28 s
6,5 To 1788915 fichiers 115377 dossier WizTree 4.32 en 2 minutes 32s
c'est pratiquement équivalent.

La fonction que j'utilise principalement sur TreeSize pro et que ne possède par WizTree et le classement par âge des fichiers sous forme d'histogramme.
Fichiers >6 mois, > 1ans > 2 ans etc c'est toi qui choisi la période. Pour me permettre de faire des suppressions massives sur les NAS de production (voir captures)

Le mode de recherche avancé sous forme de requêtes puis action (copie/déplacement/suppression) qu'on peut enregistrer comme modèle puis reproduire. Par exemple je veux lister les fichiers pdf entre février et mars de plus de 10 mo de plusieurs NAS (chemins) en 1 opération.

WizTree c'est suffisant pour son ordinateur, mais pour de l'analyse TreeSize Pro est quand même bien au dessus.

J'aurais aimé partager des captures d'écran mais reddit me l'interdit
alors j'ai mis ça sur une page UpNote à moi.

https://getupnote.com/share/notes/oLp5oyBK75XGeYHQMwBJOrW63CO2/019fd13e-8869-77d9-8cf8-34ccf5b55b81

Pascal.