How to use Folder Size Visualizer
This is the Folder Size Visualizer utility. 100% client-side and offline capable.
Folder Size Visualizer
Folder Size Visualizer
Analyze disk usage, find large files, and optimize your storage
100% Private - All analysis happens in your browser. No files are uploaded.
Common Questions
Is it safe to grant folder access? Can you see my files?
100% Safe and Private. This tool uses the modern File System Access API which keeps everything strictly within your browser. We never upload your file names, folder structures, or content to any server. All calculations happen locally on your CPU. Once you close the tab, all access is automatically revoked by your browser.
What is the difference between "Select Folder" and "Upload Folder"?
Select Folder uses the modern API (available in Chrome/Edge) which allows the tool to scan your disk very efficiently without "uploading" anything. Upload Folder is a fallback for other browsers (like Safari/Firefox) that reads the directory structure via an upload dialog. Both methods are completely local and private.
How do I read the Treemap visualization?
The Treemap represents your disk space using nested rectangles. The size of a rectangle is proportional to the size of the file or folder. Colors represent different file categories (e.g., Red for Videos, Green for Documents). Click on any folder rectangle to "zoom in" and see its sub-contents in more detail.
Can it find duplicate files?
Yes! Navigate to the Duplicates tab. The tool groups files by their exact byte size and then performs a SHA-256 hash comparison of the content to ensure they are identical. This allows you to safely identify and delete wasted space without risking useful data.
How does it handle "Permission Denied" errors?
Some system folders (like C:\Windows\System32 or /root) are protected by your Operating System. If the tool encounters such a folder, it will gracefully skip it, log the error in the "Inaccessible Paths" list, and continue scanning the rest of your files so the analysis isn't interrupted.
Can I export a report of my largest folders?
Absolutely. You can export your scan results in three formats: CSV for spreadsheet analysis, JSON for technical data processing, or PDF Summary which includes a professional print-out of your storage dashboard, top folders, and cleanup suggestions.
What are the Educational Mode features?
Designed for Computer Science students, the Educational Mode explains core file system concepts. It covers Logical vs Physical size, Block Allocation (and why small files waste space), DFS/BFS algorithms used for scanning, and how different File Systems (NTFS, APFS, EXT4) manage data.