Folder Space Map
Find which subfolders and files account for the bytes in a folder you select. Folder Space Map groups the relative paths and logical file sizes supplied by your browser, then lets you drill into the tree, compare extensions and export a report. The tool processes metadata in this page without opening file contents or changing your files.
Key features
- Interactive size-weighted treemap with folder drill-down, a collapsible folder list and breadcrumb navigation
- Exact byte totals using integer arithmetic, alongside rounded binary or decimal display units
- Large files, zero-byte files and extension totals for the current folder and its descendants
- Optional exclusion of files whose path contains a dot-prefixed name; the original selection counts remain visible
- CSV and JSON reports for the current subtree, including exact byte strings and original relative paths in JSON
- A clearly labelled synthetic example, a flat-file fallback and cancellable processing for selections up to 20,000 files
How to use
- Choose a folder you want to inspect. If folder selection is unavailable, select individual files using the flat-file fallback, or load the synthetic example.
- Review the totals. If you change the dot-prefixed file option, press Analyze selected metadata to create a fresh report.
- Open a folder from the map, folder list or table. Use breadcrumbs to move up, and inspect large files or extension totals below.
- Export the current subtree as CSV or JSON. Clear the page when finished; original files are never modified.
Use cases
- See whether pictures, archives or project assets account for most selected bytes before organizing a folder
- Locate large files in a project tree without opening their contents
- Compare extension totals and inspect zero-byte placeholders in a selected export
- Create an exact-byte inventory report for the selected subtree to review separately
Frequently asked questions
Does selecting a folder upload or open its files?
The analyzer reads only File metadata: relative path, name and size. It does not read contents, upload the selection or change the original files. Metadata stays in page memory and is cleared when you clear or leave the page. A report you explicitly download contains file and folder names.
Why can these totals differ from a disk-space utility?
These are logical file sizes for the files the browser actually supplies, not allocated disk blocks or free drive space. Empty folders and files not returned by the browser cannot appear. Permissions, symbolic links, hard links, compression and filesystem accounting can produce different results; this page does not scan your whole drive.
What if folder selection is unsupported, denied or cancelled?
Use the separate individual-file input to inspect a flat selection. It cannot recover folder hierarchy and identical file names are rejected as duplicate paths. If the browser returns no files, the page cannot reliably distinguish cancellation, an empty folder or denied access. The previous report is retained when a picker produces no new selection.
How are hidden files and extensions classified?
A file is marked dot-prefixed if any path segment starts with a dot. This does not detect operating-system hidden attributes. Extensions use the last nonempty suffix, lowercased: archive.tar.gz is gz, while README, .env and name. have no extension. File contents and MIME signatures are not examined.
Are the treemap and exported totals exact?
Byte sums are exact integers and JSON stores them as decimal strings. Treemap geometry is approximate; zero-byte files have no area, and very small items may be hard to see. More than 60 positive-size children are grouped into 59 items plus Other. Tables still list all included entries. CSV has overlapping folder, extension and file rows, so do not add every row together. Import byte columns as text to avoid spreadsheet rounding.
What are the limits and how can I stop processing?
A selection may contain 20,000 files and create up to 20,000 folders, with at most 32 directory segments per file. Paths are limited to 1,024 UTF-16 code units, each segment to 255, and combined stored file/folder paths to 8 million. Individual sizes must be nonnegative safe integers. Processing yields regularly; Cancel or Escape discards unfinished results. The visible folder list is capped at 200 rows, and tables use 50-row pages.
Privacy
Selected paths and sizes remain in this page’s memory. The tool does not read file contents, upload metadata, save a session or rename/delete source files. CSV and JSON downloads contain the chosen subtree’s names and sizes; review them before sharing.
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