Folder Size Analyzer

How folder selection works

The tool checks whether showDirectoryPicker from the File System Access API is available. When it is, click Choose folder and select a folder in the folder picker. If that feature is not available, the tool uses a webkitdirectory directory-input fallback when the browser supports it. If neither option is available, it shows an unsupported message. You must explicitly select the folder; the tool does not choose one automatically.

Tree view, Flat list, and treemap

Tree view opens one folder at a time. Click a folder to drill down, then use the breadcrumbs to return to a parent folder. Flat list shows sortable columns for the scanned items. Search and filters apply to these two views.

The Treemap uses block area to represent item size and shows up to 60 items in the current folder. Click a folder block to drill down; file blocks are not navigable. The treemap does not apply the search and filter controls.

Scan progress and cancellation

Large folders can take a while to scan. The progress indicator reports scanned items, files, and folders. Click Cancel to stop an asynchronous File System Access API folder walk; partial results are discarded. With the directory-input fallback, the file list is processed synchronously, so Cancel may not take effect until that processing finishes.

Filtering, sorting, and result limits

Search by name or path, or filter by type, category, extension, minimum or maximum size in KB, and modified-date range. Click Clear filters to reset these controls. Top extensions shows the ten largest extension groups.

Flat list displays at most 2,000 matching rows. The result count may be higher; narrow the filters to reveal more rows. CSV and JSON export the full filtered list, not only the displayed rows.

Exporting results

Use CSV or JSON to export the full currently filtered list. The export includes each item's name, path, type, category, extension, size, and modified date. The JSON file also includes totalSize and itemCount.

What this tool is not

This is a read-only reporting tool. It never deletes, moves, uploads, hashes, or compares any file, and it never reads file contents - only metadata. If you're trying to find byte-identical duplicate files instead of a storage breakdown, that's a different tool: try the Duplicate File Finder, which hashes file content to group exact duplicates.

How to analyze a folder's size

1. Click Choose folder and select a folder in your browser's or OS's picker.
2. Wait for the scan to finish. During an asynchronous folder walk, click Cancel if needed.
3. Review the stat cards, category/extension breakdowns, size distribution, and last-modified summary.
4. Use Tree view, Flat list, or the Treemap to inspect the results.
5. Use the search box and filters to narrow Tree view and Flat list by name, path, type, extension, size, category, or modified date.
6. Sort Flat list by clicking a column header.
7. Export the full filtered list with CSV or JSON.
8. Click New scan to select another folder.

Limitations and data handling

• Folder selection depends on feature detection for showDirectoryPicker or webkitdirectory. Some browsers show an unsupported message when neither is available.
• The scan uses file names, sizes, and last-modified dates. It does not read file contents.
• During a File System Access API scan, a metadata-access error for an individual file can create an inaccessible entry. The directory-input fallback does not provide a separate inaccessible-file mechanism.
• Very large folders take more browser time and memory. The fallback's synchronous processing may also delay the response to Cancel.
• The tool does not delete, move, rename, upload, hash, compare, or otherwise modify files.

Frequently asked questions