Comparing the Best Disk Space Analyzers for Windows
Last updated: July 2026
A disk space analyzer scans a drive, folder, or network share and shows exactly where storage is being used - ranking folders and files by size so you can reclaim wasted space. The five tools below are the most widely used disk space analyzers for Microsoft Windows. They share the same core job but differ sharply in visualization options, reporting depth, export formats, automation, and licensing.
AT A GLANCE
| Feature | FolderSizes | WinDirStat | WizTree | TreeSize | Folder Size (MindGems) |
|---|---|---|---|---|---|
| Licensing model | Free edition + perpetual Personal/Pro licenses | Free, open source (GPLv2) | Free for personal use; paid code for commercial use | Free (non-commercial); annual subscriptions | Free edition + paid Professional |
| Treemap visualization | Yes | Yes | Yes | Yes (2D/3D) | No |
| Bar & pie charts | Yes | No | No | Yes | Yes |
| Sunburst chart | Yes | No | No | No | No |
| Dedicated file report types (largest, oldest, temporary, owners, ages...) | Yes (13 types) | No | File view + types | Statistics & search views | No |
| Duplicate file detection | Yes (free edition) | Yes | Yes | Yes (Personal+) | No |
| Export formats | HTML, XML, Excel, PDF, CSV + templates (Pro) | CSV | CSV | PDF (free); Excel/CSV/HTML (Personal+) | CSV, XML (PDF in Pro) |
| Built-in scheduling + email delivery | Yes (Pro) | No | No | Professional only | CLI-based (Pro) |
| Command-line interface | Yes (Pro) | Yes | Yes | Professional only | Professional only |
| Snapshots with point-in-time comparison | Yes (Pro) | No | No | Yes (Personal+) | Saved scan files |
| Multi-point storage trend analysis | Yes (Pro) | No | No | Scan history | No |
| Network shares & UNC paths | Yes + share discovery | Yes | Yes (no MFT speed on network) | Yes | Yes |
| Cloud services (SharePoint, S3, Azure) & SSH | No | No | No | Yes (paid editions) | No |
| NTFS MFT fast-scan | No | Yes (2.x) | Yes | – | – |
| Portable mode | No | Yes | Yes | Professional only | – |
| Modern Windows & Windows Server support | Yes (Server in Pro) | Yes | Yes | Yes | Yes |
– indicates a capability not advertised in the vendor's published materials as of July 2026. Edition names in parentheses indicate the minimum edition that includes the feature.
THE TOOLS, ONE BY ONE
FolderSizes - best for reporting, automation & managing storage over time
FolderSizes (Key Metric Software, since 2003) pairs four interactive chart types - treemap, sunburst, bar, and pie - with 13 dedicated file report types, advanced multi-criteria search, and professional exports to HTML, Excel, PDF, CSV, and XML. Pro adds scheduled scans with email delivery, file system snapshots with comparison, a multi-point trend analyzer, and capacity planning. The free edition is unusually complete: search, duplicate detection, all four charts, and scan filtering with no time limit. Licensing is perpetual - pay once, no subscription. Download free Feature comparison
WinDirStat - best free open-source option
WinDirStat is free, open source (GPLv2), and beloved for its classic treemap. Largely dormant from 2007, its 2.x rewrite (late 2024) added multi-threaded scanning, NTFS MFT support, and dark mode. It remains a visualization-first tool: no file reports beyond the treemap and type list, no scheduling, no snapshots, and CSV-only export. Ideal for users who want a simple, trustworthy, zero-cost treemap. See our full FolderSizes vs WinDirStat comparison.
WizTree - best for raw local scan speed
WizTree (Antibody Software) reads the NTFS Master File Table directly, making it the fastest way to see what's on a local NTFS drive - often scanning in seconds. The speed advantage requires local NTFS and admin rights; on network shares it enumerates like everyone else. Reporting, export (CSV only), and automation are minimal by design. Free for personal use; commercial use requires a paid supporter code. See our full FolderSizes vs WizTree comparison.
TreeSize - best for cloud & remote targets
TreeSize (JAM Software, Germany) is a mature, polished analyzer whose paid editions uniquely scan SharePoint, Amazon S3, Azure, and Linux systems over SSH, and can deduplicate files via NTFS hardlinks. Its editions are sharply tiered: TreeSize Free is non-commercial only with no search or duplicate finder, and scheduling/CLI require the Professional subscription. Paid editions are annual per-user subscriptions. See our full FolderSizes vs TreeSize comparison.
Folder Size (MindGems) - best for a lightweight free size explorer
MindGems Folder Size is a lightweight, Explorer-style folder size browser with bar and pie charts. It scans local and network storage and exports to CSV and XML, with printing, PDF export, and command-line automation reserved for the Professional edition. It has no treemap, duplicate detection, snapshots, or trend analysis - a simpler tool for simpler needs.
HOW TO CHOOSE
- "What's filling my C: drive right now?" - WizTree (fastest local scan) or WinDirStat (open source).
- "I need reports my boss/auditors can read." - FolderSizes (Excel/PDF/HTML exports with templates).
- "I manage file servers and need scheduled, automated analysis." - FolderSizes Pro (built-in scheduler + email) or TreeSize Professional.
- "I need to analyze SharePoint or S3 buckets." - TreeSize Professional (unique in this group).
- "I want to track storage growth over time." - FolderSizes Pro (snapshots + multi-point trend analyzer + capacity planning).
- "I just want a free tool with no strings." - WinDirStat (GPLv2), or the FolderSizes free edition for more analysis depth.
Want the deeper technical background? Read our explanation of what a disk space analyzer is, our guides to finding large files and recovering disk space, or the detailed head-to-head comparisons: vs WinDirStat, vs WizTree, and vs TreeSize.