Split a Video Into Equal File Sizes

For USB drives, upload caps, or a fixed number of storage devices — splitting by size, not length, is what actually solves the problem.

Splitting by file size — rather than by length or clip count — means every piece lands at or under a target size you set, like 10 GB, with the last piece simply being whatever's left over. It's the right approach when you're working around a hard limit: a USB drive's format ceiling, an upload cap, or a fixed number of Blu-rays or storage devices.

When to split by size instead of by length

• Transferring to FAT32 drives — which cap individual files at 4 GB regardless of drive capacity
• Upload limits — cloud storage, email attachments, or platforms with a per-file cap
• Splitting across physical media — fitting footage onto a specific number of drives or discs
• Archiving to a fixed budget — e.g. "give me 20 GB pieces so I know exactly how many drives I need"

Splitting by length or clip count doesn't guarantee any of this, since video bitrate varies — a 10-minute action scene can be twice the size of 10 minutes of static footage. Only size-based splitting targets the actual constraint you're working around.

How size-based splitting actually works

A precise byte-for-byte split isn't possible without breaking the video format itself — container formats need clean cut points. The practical approach: cut a chunk at your target size, measure exactly how far into the video that chunk reached, then start the next chunk from that exact point. Repeat until the file is exhausted. Done this way, each chunk lands at or just under your target size, and the last one is naturally whatever's left over — no wasted space, no guessing.

Size-based vs. length-based: which should you use?

You need	Use
Clips that fit a storage or upload limit	Split by size
An exact number of equal-length clips	Split by count
Clips of a specific duration (e.g. 1-hour chunks)	Split by length

Can I split a video into exact 10GB pieces?

You can get chunks that land at or just under 10 GB each, with the very last chunk being the remainder. An exact byte-for-byte split isn't possible without breaking the video file format, since cuts have to happen at valid points in the video stream.

Why is my last split chunk a different size than the rest?

This is expected and correct. When splitting by size, every chunk targets your chosen size except the final one, which is simply whatever footage is left over after all the full-size chunks are cut.

Does splitting by size affect video quality?

No, as long as the tool uses stream copy rather than re-encoding. The video data itself is unchanged — only repackaged into smaller files at the size-based cut points.