Freedom251 › Disk Space Analyzers
DiskSizer
What DiskSizer is
DiskSizer is a free, open-source Windows utility for finding what occupies space across drives. It presents files and folders in interactive D3 sunburst and treemap charts, sizing each area according to storage use and allowing directory drill-down. A scan overlay shows files and sizes as they accumulate. The software detects drive type through Windows Management Instrumentation and changes its scanning method accordingly. On hard disk drives, a native C++ addon reads sizes from directory entries with Windows FindFirstFileExW rather than making per-file stat calls. Its in-memory-first scanner keeps 64 directory reads active at once, while solid-state drives use unlimited parallelism. The site reports 1.18× faster scans on trees of at least three million files, 1.92× faster scans on smaller directories, and 73% lower heap usage. DiskSizer uses Electron 28, React 18, D3 v7, TypeScript, Tailwind CSS, and a C++ N-API addon. Downloads are linked through GitHub, with GitHub Issues for problems.
Who it suits
DiskSizer suits Windows users who need a visual view of drive usage and want to identify storage they may reclaim. It is also suited to readers seeking free, open-source software.
What it does well
- Interactive sunburst and treemap views
- Directory drill-down by storage size
- Drive-type-aware scanning
- Free forever and open source
- GitHub Issues support
What to know first
- Windows only
- No free trial is offered
- Performance figures are site-reported
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Free | Free forever · open source | Free |
As disksizer.whhite.com lists them, read 12 Oct 2026. The maker's own page has the final word.
Verdict
DiskSizer focuses on visual disk analysis, combining proportional charts with scanning methods tailored to HDDs and SSDs. Its free, open-source distribution and GitHub support make it accessible for Windows storage analysis.
Facts from DiskSizer's own pages
- Charts
- It offers interactive D3 sunburst and treemap views that visualize files and folders in proportion to their size and support directory drill-down. · disksizer.whhite.com, 12 Oct 2026
- Distribution
- The site describes DiskSizer as free forever and open source, and links to its GitHub repository for download. · disksizer.whhite.com, 12 Oct 2026
- Drive detection
- DiskSizer auto-detects drive type through WMI. · disksizer.whhite.com, 12 Oct 2026
- Free plan
- Yes · disksizer.whhite.com, 22 Sept 2026
- HDD scanning
- On HDDs, a native C++ addon uses Windows FindFirstFileExW to read file sizes from directory entries without per-file stat() calls. · disksizer.whhite.com, 12 Oct 2026
- Intended audience
- The site presents DiskSizer as a tool for understanding disk usage and reclaiming storage on Windows. · disksizer.whhite.com, 12 Oct 2026
- Performance
- The site reports 1.18× faster scans on large trees of 3M or more files, 1.92× faster scans on smaller directories, and 73% lower heap usage. · disksizer.whhite.com, 12 Oct 2026
- Platforms
- The product is described as a Windows desktop app built with Electron 28. · disksizer.whhite.com, 12 Oct 2026
- Purpose
- DiskSizer is a Windows disk space analyzer for seeing what is using storage across drives. · disksizer.whhite.com, 12 Oct 2026
- Scanner design
- Its In-Memory First scanner keeps 64 directory read requests in flight simultaneously; on SSDs it runs with unlimited parallelism. · disksizer.whhite.com, 12 Oct 2026
- Scan progress
- A progress overlay shows files and sizes accumulating while a scan runs. · disksizer.whhite.com, 12 Oct 2026
- Scan scope
- files_folders · disksizer.whhite.com, 22 Sept 2026
- Support
- The site links to GitHub Issues for reporting issues. · disksizer.whhite.com, 12 Oct 2026
- Technology
- The listed stack includes Electron 28, React 18, D3 v7, a C++ N-API addon, TypeScript, and Tailwind CSS. · disksizer.whhite.com, 12 Oct 2026
- Treemap view
- Yes · disksizer.whhite.com, 22 Sept 2026
Where DiskSizer stands on Freedom251
- Disk Space Analyzers#63 of 105