Disk Space Analyzer — Free Online Folder Size Scanner

A disk space analyzer scans your folders and files and shows you how much storage each one uses. It helps you quickly identify what is taking up space on your hard drive or SSD so you can decide what to delete, move, or archive to free up disk space.

Yes, completely free — no limits, no watermark, no ads. There is no account to create and no subscription. It is one of the free browser-based tools at jasperbernaers.com.

No. It runs entirely in your web browser, so there is nothing to download or install and no account to create. Just open the page, click Choose Folder and scan — ideal for locked-down or managed work machines where you cannot install desktop software.

No. This tool runs 100% in your browser using the File System Access API. Your files are never uploaded to any server. Only file names and sizes are read — file contents are never opened. You can verify this in your browser's network tab: zero outbound requests carry your data.

Yes. File contents are never read — only names and sizes. Nothing leaves your browser. The File System Access API requires you to explicitly grant permission for each folder you scan, so there is no risk of scanning something unintentionally.

It needs the File System Access API, supported in Google Chrome 86+, Microsoft Edge 86+, and other Chromium browsers such as Brave, Opera and Arc. If you open it in an unsupported browser, a compatibility notice appears at the top of the page.

Not yet. Firefox and Safari do not implement the folder-picking File System Access API that this tool relies on, so full-drive scanning is not available there. Use a Chromium-based browser such as Chrome, Edge, Brave or Opera for the best experience.

Yes. Because it runs in the browser, it works on any operating system with a Chromium browser — Windows, macOS, Linux and ChromeOS — with no platform-specific install.

It is designed for desktop. Most mobile browsers do not expose the folder-scanning File System Access API, so whole-folder analysis works best on a Windows, macOS, Linux or ChromeOS computer.

Yes. When the folder picker opens, navigate to your drive root (C:\ on Windows or / on macOS/Linux) and select it. The scan recursively walks all subfolders. Some system-protected folders may be skipped if the OS denies access — this is normal and expected.

Yes, as long as the drive is mounted and visible to your operating system. Just navigate to it in the folder picker. Scanning speed depends on the network or USB connection speed.

No — the analyzer is read-only and never modifies or deletes anything. It only reads names and sizes so it can show you where your space has gone. Once you have spotted the large folders, delete or move them yourself in File Explorer, Finder or your file manager.

Yes. Click Export CSV to download a full inventory of every folder and file with its size and file count. Open it in Excel, Google Sheets or a text editor, or share it with your team.

WinDirStat, TreeSize and WizTree are Windows desktop applications that require installation (WizTree is faster because it reads the NTFS master file table directly). This tool works right in your browser with nothing to install, on any OS — ideal for quick checks or machines where you cannot install software.

Scanning reads metadata (name and size) for every file in every subfolder recursively. A folder with hundreds of thousands of files or deeply nested subfolders takes longer. A live progress counter shows the tool working in real time, including the folder it's currently reading.

Each bar shows how much of the parent folder's total size that item represents. A bar at 80% means the subfolder or file accounts for 80% of its parent's disk usage, so you can spot the biggest space consumers at a glance.

The tool reports the logical size of files (the number of bytes). Your OS may show size on disk, which differs because of filesystem cluster/allocation sizes and compression, and it may include files this tool skipped when the OS denied access. Small differences are normal.

Scan your drive, sort by size, and expand the largest folders. Common culprits are forgotten downloads, old backups and disk images, media caches, and developer folders like node_modules and .git. Confirm what each big folder is, then delete or move it in your file manager and rescan to see the space you reclaimed.

The treemap is a colored map where every rectangle is a file or folder and its area is proportional to its size — the bigger the box, the more space it uses. It's a fast way to spot the one huge box that's eating your disk without scrolling through a long list. Switch to it with the Treemap button above the results, or press T.

Each box is colored by what kind of content it mostly holds — for example cyan/blue for images, pink for video, purple for audio, orange for archives, green for code, and so on. A folder box that hasn't been split into its own children yet is colored by its dominant file type, so you can tell at a glance whether a big region is mostly video, code, or archives before you even open it. The same colors are used in the Top File Types panel and its legend below the treemap.

Yes. Hover any folder row in Tree view and click the 🔍 icon, or click a folder's label inside the Treemap, to make that folder the new focus. The stats, the Top File Types panel and the Largest Files panel all update to reflect only what's inside it.

Use the breadcrumb trail above the results (for example 📍 root ▸ Users ▸ Downloads) — click any earlier segment to jump back to that level, or click the first segment, or press Escape, to return to the full scan.

It groups every file in the current view by extension (.jpg, .mp4, .log, and so on) and shows how much space each type uses, sorted largest first. Click a row to instantly search for files with that extension.

A ranked list of the biggest individual files inside the folder you're currently viewing — the fastest way to find that one forgotten large video or database dump without expanding the whole tree.

Yes. Type into the search box above the results, or press / to jump to it, and the tree or treemap instantly filters down to matching files and folders, automatically expanding their parent folders so you can see where they live. Clear the box or press Escape to go back to the full view.

Yes, your last Tree/Treemap choice, sort order and expand depth are saved in your browser's local storage so the next scan opens the way you left it. Nothing about the files or folders you scanned is ever saved or sent anywhere.

When a folder has more items than can be usefully shown at once, the smallest ones are grouped into a single "+N more" box so the treemap stays readable and fast. Switch to Tree view, or zoom into that folder, to see more of it individually.

Yes — / focuses the search box, E expands the whole tree, C collapses it, T switches between Tree and Treemap view, and Escape clears the search or zooms back out one level.

Scanning stays responsive because it yields to the browser regularly and shows a live counter, but very large drives (500,000+ files) can take a few minutes since every file's metadata has to be read one by one through the browser's File System Access API. The treemap automatically caps how many boxes it draws at once so rendering stays smooth regardless of folder size — zoom in for more detail on a specific area.

Tree view is a sortable, expandable list — best for scanning names, exact percentages and file counts row by row. Treemap view is a proportional map — best for instantly spotting the single largest thing at a glance. Both stay in sync with the same search, zoom and sort settings.

No. Export CSV always exports the full inventory from your last scan, regardless of how you've zoomed, searched, sorted or filtered the on-screen view, so you always get the complete picture in your spreadsheet.

Yes. Clicking any row in the Top File Types panel searches for that extension, filtering the tree or treemap down to just those files so you can see exactly where your photos, videos or logs are scattered.