Compress WebM
Shrink a WebM file and turn it into a widely-compatible MP4 — all locally in your browser, nothing uploaded.
Drop a video here, or browse
MP4 · MOV · WebM — compressed right here, nothing uploaded
100% on-device · no signup · no watermark
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Bigger files take longer — your CPU does the work, privately.
WebM is efficient — but not always accepted
WebM (VP8/VP9) is a great web format, but some apps, messengers and editors don’t accept it. Re-encoding to MP4 (H.264) makes the file play everywhere, and lets you hit a specific target size for sharing.
Screen recorders and browser tools often export WebM; this compressor turns that into a smaller, ready-to-share MP4.
Frequently asked questions
Can I convert WebM to MP4 here?
Yes — the compressor reads WebM and outputs an H.264 MP4, which is smaller to share and accepted by virtually every app and platform.
Why won’t my WebM upload somewhere?
Some platforms only accept MP4. Converting and compressing to MP4 here solves both the format and the size in one step.
Does it run on a server?
No — it runs entirely in your browser. Your file is never uploaded.
Is it free?
Yes, completely free with no signup and no watermark.