Compress a WebM video and keep it WebM

Most online compressors turn WebM into MP4. This keeps the format: VP9 video in a WebM file, just smaller — ready for a website or a browser recording.

Your files stay on your device. Nothing is uploaded.

Drop videos here

File	Length	Size	Result

Estimates may change after processing.

If a video doesn’t fit — split it into parts Keep capture date and location

Preset

Have technical requirements (a spec)?

Upload them — PDF, DOCX, TXT or just a screenshot. We’ll read the spec, set everything up and tell you what’s missing or impossible.

Size & quality Fit to size (slider above) Fixed bitrate Mbps Quality level Bitrate mode

Video Format Container Frame rate Keyframe every, s Rotate Encoder

Sound Codec Bitrate Sample rate Channels Loudness Peak no higher than

Trim, split & name Start of the clip (min:sec) End of the clip (min:sec) Split into parts Part length, s Add to file name

When to keep WebM

Videos on your own website: WebM with VP9 is usually noticeably smaller than MP4 (H.264) at the same quality and plays in every modern browser.
Screen recordings from the browser and OBS clips that are already WebM.

When to choose MP4 instead

Sending to phones, WhatsApp, email or TVs — MP4 (H.264) opens everywhere. Pick “Plays anywhere” or any messenger preset.
Safari on older iPhones and Macs doesn’t play WebM.

Want a target size?

The preset compresses by quality. To hit an exact size, open Advanced settings and switch to a target size — the result stays WebM.

Questions

Does it convert WebM to MP4?

Not on this page — the result stays WebM. Choose the “Plays anywhere” preset if you need MP4.

Which codecs does the WebM use?

VP9 video and Opus audio. If your browser can’t encode VP9, the file is saved with the best codec it can.

Is there a file size limit?

No. The video is compressed on your device, never uploaded.

Last updated: 2026-10-30

See also