How to compress a video to a target file size

Start with the upload limit and duration

If a destination has a strict limit, leave some space below it. A longer video must spread the same byte budget across more seconds. At a fixed duration, lowering the target usually reduces the detail available in each frame.

FormatOwl’s target-size field uses MiB internally: one unit is 1,048,576 bytes. Some destinations use decimal MB instead. Compare the final byte size when the distinction matters.

Choose the settings in FormatOwl

Open Video compressor and upload MP4, MOV, MKV or WebM. In Advanced compression, enter a target size. H.264 is a useful starting point for playback compatibility. Keep the original resolution first, then try 720p or 480p if the available bitrate makes the picture look blocky.

Target mode runs two encoding passes. Its result can vary slightly, and an impractically small target can be rejected. A slower encoding preset may improve compression efficiency, but processing takes longer.

Compare the output, not just the number

Compare fast motion, small text and dark scenes in the original and compressed previews. Listen for audio problems. Raise the target if essential details disappear, and keep the original file until you have checked the full result.

Changing the container alone does not guarantee a smaller video. Use video conversion for a format requirement and compression for a size requirement. FormatOwl processing happens on the server after upload; it is not an offline browser-only compressor.

Measured synthetic motion sample

Measured locally on September 16, 2026 with a generated test pattern and no audio. This is a demonstration, not a promised compression ratio. Real footage, audio, encoder versions and settings change the result.

Related tools

• Video compressor
• Convert video
• MOV to MP4