File Chunking

Split large files into smaller chunks or combine them locally in your browser.

Tool Requires Desktop

The File Chunking tool uses advanced browser capabilities (like the File System Access API) which are not fully supported on mobile browsers.

Please visit this page on your computer to use the tool.

How It Works

  1. Select Your File

    Drag and drop or browse to select any file you need to split. There are no file type restrictions — videos, archives, disk images, and more are all supported.

  2. Set Your Chunk Size

    Use the slider or type a value to choose the maximum size for each chunk. With supported browsers (Chrome, Edge), you can go up to 5 GB per chunk. Otherwise, the limit is 500 MB.

  3. Choose an Output Folder

    On supported browsers, you’ll pick a folder where chunks are saved directly. On others, each chunk downloads individually to your default downloads folder.

  4. Done — Chunks Are Ready

    Your file is compressed with Zstandard (zstd) and split into numbered .zst.001, .zst.002, … files. Come back to the Combining tab whenever you need to reassemble them.

Features

100% Browser-Based

Your files never leave your device. All splitting and combining happens locally using WebAssembly — nothing is uploaded to any server.

Zstandard Compression

Files are compressed with zstd (level 3) as they’re split, so your chunks are often significantly smaller than the original file.

Flexible Chunk Sizes

Set chunk sizes from 1 MB up to 5 GB (or 500 MB on browsers without File System Access API support).

Split & Reassemble

Switch between the Chunking and Combining tabs. Combining decompresses and merges chunks back into the original file — including folder mode for convenience.

Desktop Optimized

On supported desktop browsers, files are streamed directly to and from disk, keeping memory usage low even for very large files.

Frequently Asked Questions

Is my file uploaded to a server?
No. Everything runs locally in your browser using WebAssembly. Your file data never leaves your device.
What file types can I split?
Any file type. The tool treats files as raw binary data — it doesn’t matter whether it’s a video, ISO image, database backup, or anything else.
What compression algorithm is used?
Files are compressed using Zstandard (zstd) at level 3, which provides a good balance of compression ratio and speed. This means your chunks will often be smaller than the original file.
What are the .zst.001 files?
These are your split chunks. Each chunk is a compressed fragment of the original file, numbered sequentially. To reassemble them, use the Combining tab on this page.
What’s the maximum chunk size?
On browsers that support the File System Access API (like Chrome and Edge), the maximum is 5 GB per chunk. On other browsers, it’s limited to 500 MB to avoid excessive memory usage.
Can I combine chunks that were split with a different tool?
No. The chunks must have been created by this tool because they use Zstandard compression with a specific framing format. Standard split/cat tools won’t produce compatible chunks.
Does this work on mobile?
The Chunking tool requires desktop browser features (File System Access API or large download support) and is not available on mobile devices.