WizTree

Everything

Everything is a Windows desktop utility from voidtools that indexes file and folder names across NTFS and ReFS volumes to deliver search results in real time, often before you finish typing. Instead of scanning the disk on demand like Windows Explorer's built-in search, it reads the NTFS Master File Table (or ReFS equivalent) once to build a compact index, then uses the USN/Change Journal to keep that index updated live as files are created, renamed, or deleted.

GrandPerspective

GrandPerspective is a free macOS utility that scans a folder or volume and displays disk usage as a treemap, where each file is drawn as a rectangle sized proportionally to how much space it consumes. This makes it fast to spot the largest files and folders visually rather than digging through nested Finder windows. Released under the GNU General Public License, GrandPerspective supports multiple color-mapping schemes (by file type, size, or modification date), filtering and search, and can compare or combine multiple scans. It is distributed for free from SourceForge, with an optional paid copy on the Mac App Store for users who prefer automatic updates and app-review verification.

TreeSize Free

TreeSize Free, by JAM Software, is a free disk space analyzer for Windows that shows which folders and files are consuming storage. It presents a treemap visualization of disk usage and can generate PDF reports, making it easy to spot what is taking up space on a drive.

WinDirStat

WinDirStat is a free, open-source disk usage analyzer for Microsoft Windows that scans drives and folders and shows how disk space is distributed across the file system. It uses multithreaded scanning with direct NTFS support and presents results as sortable lists, extension statistics, a Largest Files view, and an interactive treemap that makes it easy to visually spot which folders and file types are consuming the most space. Beyond basic scanning, WinDirStat can detect duplicate files by content, inspect file permissions, and analyze storage tiers, and it supports file operations like opening, moving, or deleting items directly from the results view. It also offers dark mode, Windows Explorer integration, file-system change monitoring, and scan export, and is distributed under the GNU General Public License version 2 (GPLv2) with source code hosted on GitHub.