✂️ Split a file

How to put the file back together

The pieces are numbered yourfile.zip.001, .002 and so on, and each one is a plain slice of the original with nothing added. That matters, because it means the person receiving them is not dependent on this site — or on any site.

On Windows, from the folder holding the pieces: copy /b yourfile.zip.* yourfile.zip. On macOS or Linux: cat yourfile.zip.* > yourfile.zip. Both work offline. If they would rather not touch a terminal, the join files tool does the same thing in a browser.

Choosing a piece size

Pick the size from whatever is doing the limiting. Most email providers stop at 25 MB per message including the encoding overhead, which is why 25 MB is the default here. Chat apps and web upload forms are usually more generous but rarely say so until the upload fails. If the limit is a physical disc or an old USB stick formatted as FAT32, the ceiling is 4 GB per file regardless of how much space is free.

Fewer, larger pieces are easier to keep track of. More, smaller pieces survive a flaky connection better, because a failed transfer only costs you one piece.

Your file stays on your machine

The browser reads the file directly from disk and slices it locally. Nothing is sent anywhere, there is no server to have a copy, and closing the tab leaves no trace. That is the practical reason to split a file in a browser rather than through an online service: the files large enough to need splitting are usually the ones you would least like to hand to a stranger.

Very large files

Slicing does not load the whole file into memory, so multi-gigabyte files work. What can strain a browser is the number of downloads rather than their size — several hundred pieces will make most browsers ask whether you really want that many files. If you are heading toward triple digits, use a larger piece size.