Split Video cuts one large file into many small ones mechanically: an upload platform caps the file size, WeChat sends only a short clip at a time, or a 2-hour lecture has to go out in 10-minute parts. It is the “Split” tab of the audio/video workbench and uses ffmpeg's segment muxer with -c copy — no decoding, no re-encoding — so a few gigabytes are cut in under a minute.

There are two ways to set the cut: “By duration” takes minutes per part (decimals work: 0.5 is 30 seconds); “By size (estimated)” takes a target MB per part, which the tool converts into a duration using the file's average bitrate, so the real sizes vary. Both video and audio files can be split, and the output keeps the source container (MP4 stays MP4, MP3 stays MP3; rarer containers fall back to MKV / MKA).

1. 01Add a file and select it— video or audio; switch to the “Split” tab.
2. 02Choose the method— “By duration” takes minutes per part (5 by default); “By size (estimated)” takes MB per part (100 by default) and falls back to a hint to use duration when no bitrate information is available.
3. 03Check the preview— the panel writes “about mm:ss per segment, N segments expected”; for video it also reminds you that cuts align to keyframes.
4. 04Split and download— click “Start splitting” and then “Download”, which packs a zip of <original-name>_part000.mp4, <original-name>_part001.mp4 … numbered with three digits.

Cut precision

— video can only break at keyframes, so each part may start and end a few seconds away from the setting; audio (MP3, AAC, WAV) is essentially exact.

Size mode is an estimate

— it divides file size by duration to get an average bitrate, so videos with a wildly varying bitrate (action footage, screen recordings) end up with clearly uneven parts.

Output follows the source

— you cannot convert while splitting; WMV, RMVB and similar files land in an .mkv container.

Part count and memory

— all parts are generated in memory before zipping, and a few hundred small files take a moment to pack.

What it does not do

— it is not “take one section” (for start and end times use “Video trim”), it cannot take a list of unequal cut points, and it never re-encodes, so it does not compress either.

Files are split and packed locally in the browser by ffmpeg.wasm and are never uploaded to a server. The first time, the engine of about 31 MB is downloaded from a CDN (the site asset domain or jsDelivr); that request contains no file content.