What is taking up disk space on Windows? Find out in minutes

Short answer: Windows shows only rough categories in Settings → System → Storage. To see the exact folders and files behind the numbers, use a free analyzer like Disk Space Analyzer: it scans the drive in about a minute, draws folders and files as a clickable treemap and lists the 500 largest files — then unneeded items go to the Recycle Bin.

Why the drive fills up

Disks rarely fill with things you remember. The usual suspects:

  • hundreds of gigabytes of games and video projects;
  • caches of browsers, messengers and video editors;
  • a Downloads folder that has "temporarily" held everything since last year;
  • phone backups, Windows.old after a big update and system restore points;
  • the same videos in three copies, "just in case".

Method 1: Storage settings (what Windows shows)

Open Settings → System → Storage. Windows 10 and 11 group the space into categories: Apps & features, Pictures, Documents, Temporary files and so on.

This is useful for a quick overview, but the categories are approximate and cannot be opened: you see "Pictures — 42 GB", but not which folder holds those gigabytes. Storage Sense can remove temp files and old Downloads automatically, yet it never shows where the space actually went.

Method 2: File Explorer (manual)

In File Explorer you can sort the contents of a folder by Size (View → Details, then click the Size column). This finds big files in the folder you are looking at, but:

  • folders have no size column — to measure one you would have to enter it and sum the files;
  • you must go folder by folder manually;
  • hidden and system objects are easy to miss.

For a handful of files this is fine; for a full disk it is a dead end.

Method 3: a free treemap analyzer — Disk Space Analyzer

Disk Space Analyzer does the whole job:

  1. Pick a drive or folder and press Analyze. Only metadata is read, no file contents, so the scan is quick. System folders (Windows, Program Files, AppData) can be skipped.
  2. Look at the treemap and the category bar. Every folder and the largest files become blocks whose area equals their real size — the culprit is usually obvious in one look. Click a block to drill into a folder and keep going until you find it. Hovering shows name and size.
  3. Check the largest files list. The top 500 files with their folders and dates: open them, show them in Explorer, copy the path or move them to the Recycle Bin. Whole folders can be recycled too, after a confirmation.

After each deletion the totals and the treemap are recalculated instantly — no need to rescan.

Download free — DiskSpaceAnalyzer-Setup.exe

Where to start cleaning

  • Downloads and Documents — the classic dumping grounds; sort by size and sort out what you have not opened in a year.
  • Videos — the heaviest files; move the ones you keep to an external drive.
  • Duplicated media — photos and videos saved twice; a duplicate finder handles that (guide on duplicate files).
  • Games — uninstall what you no longer play (Steam and launchers free the space correctly).
  • Skip Windows, Program Files and AppData unless you know exactly what you are deleting.

How to delete safely

  • Everything the analyzer sends to the Recycle Bin can be restored — check the Recycle Bin before emptying it.
  • If a folder is synced (OneDrive, Google Drive), deleting there deletes it everywhere.
  • On external drives the Recycle Bin may be unavailable and files are removed for good — review twice.
  • Do not touch folders of installed programs: their "duplicates" may be required at runtime.

FAQ

Does Windows have a built-in disk space analyzer?

Only partially. Settings → System → Storage shows approximate categories and cannot show file-level details; File Explorer has no folder sizes. A dedicated analyzer is the practical way to find what is eating the space.

Is Disk Space Analyzer free?

Yes — free for Windows 10/11 (x64), with no ads, accounts or telemetry. The installer is called DiskSpaceAnalyzer-Setup.exe.

How long does the scan take and does it change anything?

Only metadata is read, so a typical drive takes about a minute and nothing on the disk is modified. The app itself never deletes anything: files and folders go to the Recycle Bin only when you ask.

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