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MP4 to WEBM smaller video for your own website

Every converter here is free, full size, no account.Photos convert in your browser and never leave it. Video and e-books do need our server — those we delete right after.

By ShinobiTools Team · Last updated: August 2026

Drop in an MP4 and get a WEBM back. Same picture, a noticeably smaller file, and it plays in every current browser. No account, no watermark.

Why WEBM is smaller

WEBM here uses VP9, a newer codec than the H.264 inside most MP4 files. Newer codecs find more ways to describe the same picture with fewer bits — typically 25 to 40 percent smaller for the same visual quality on real footage. The trade is time: encoding takes longer than a straight MP4 copy would.

When to use it, and when not

Use it for video you host yourself: a background clip, a product demo, anything with a <video> tag on your own page. Every current browser plays WEBM, and the smaller file means it starts sooner.

Do not use it for a file you are sending to a person. Older desktop players, some phones and plenty of editing programs will not open it, and then you have made a smaller file that nobody can watch. Send those an MP4.

A note on browsers and Safari

Safari has played VP9 in WEBM since version 14 (2020), so on any Mac or iPhone kept reasonably up to date it works. If your audience includes people on much older hardware, the safe pattern is two source files in the video tag — WEBM first, MP4 as the fallback — and the browser picks.

About your file

This runs on our own machine, not in your browser. Your file is deleted the moment the result is ready. Limit: 400 MB per upload.

Need to shrink the file to a target size instead of just the format? Compress video does that. Want an exact resolution too? Resize video handles that.

Common questions

Is WEBM better than MP4?

Smaller at the same quality, but supported in fewer places. WEBM for video on your own website, MP4 for anything you send to a person.

How much smaller is it?

Typically 25 to 40 percent on real footage. Animation and screen recordings often do better than that.

Does Safari play WEBM?

Yes, since Safari 14 in 2020. For much older devices, list a WEBM and an MP4 as two sources in the video tag and let the browser choose.

Why does it take longer than other conversions?

VP9 does more work per frame to get the file smaller. That is the trade you are making.

Can I go back to MP4?

Yes — the format converter takes WEBM in and gives MP4 back.

Is there a watermark?

No. Nothing is added to the file.