What video formats can I convert to WebM?

You can upload MP4, MOV, or WebM and convert to WebM. (Yes, WebM in and WebM out works too — handy when you want to re-encode an existing WebM smaller or strip its audio.) Images like JPG and PNG are supported as inputs for still and animated formats, but WebM output is for video sources.

Will my WebM keep its sound?

That's your call. Keep the audio track for a clip with sound, or drop it to produce a silent WebM — the right choice for autoplaying background videos and loops, which browsers will only autoplay when they're muted. Toggle audio on or off before you export.

Why convert to WebM instead of MP4?

WebM usually produces a noticeably smaller file than MP4 at comparable quality, and it's open and royalty-free, which is why it's a favorite for web video and background motion. MP4 has wider reach on older devices, but for modern browsers and page-speed-sensitive pages, WebM is often the lighter, web-native choice.

Is there a limit on video length or size?

There are sensible caps to keep conversions fast and the free tool fair for everyone, so very long or very large files may be rejected. For most clips you'll be well within range. If your video is on the longer side, use the trim controls to export just the section you need.

Do I need an account, and what happens to my file?

No account is required — the converter is free and anonymous. Your upload is processed on the server and automatically deleted within about an hour, and the result never carries a watermark. A free account is optional, and a one-time Pro upgrade adds a permanent library, reusable presets, and batch conversion if you want them.

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Video to WebM Converter

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WebM is the format the web actually wants. It plays natively in modern browsers, streams without a heavy player, and stays far smaller than the same clip as MP4 — which is exactly why it shows up behind hero videos, product loops, and background motion on fast sites. LightBox turns your video into WebM right from your browser, with the controls that matter and none of the desktop-software overhead.

Drop in an MP4, MOV, or WebM and tune it before you export: pick a quality target, set the fps, trim to the moment you need, crop or resize to fit the slot it'll live in, and choose whether to keep the audio track or strip it for a silent loop. FFmpeg does the encoding on our servers, so you get a real, properly muxed WebM — not a renamed file that breaks on upload.

It's free, anonymous, and watermark-free. Your upload is processed and then auto-deleted within about an hour, so nothing lingers. No account, no install, no catch — just a WebM you can ship.

Lighter files, native playback

WebM is built for the web: it plays directly in modern browsers with no plugin and lands far smaller than the same clip as MP4. That means faster page loads for hero videos, product demos, and looping backgrounds — without trading away picture quality.

Encode controls that match the use case

A background loop and a tutorial clip don't need the same settings. Dial in quality, fps, and resolution, trim to the exact in and out points, crop to the frame you want, and keep or drop audio. You decide the tradeoff between size and fidelity instead of accepting a one-size export.

Real FFmpeg, not a rename

Conversion runs server-side through FFmpeg, so you get a correctly encoded WebM that uploads and plays everywhere it should. Files are processed and auto-deleted within about an hour, there's never a watermark, and you don't need an account to start.

Free forever. Pro when you need more.

Everything on this page stays free. Pro adds this — once, no subscription, ever:

1 GB uploads, no daily limit
Batch convert + saved presets
Permanent library, priority processing

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Frequently asked questions

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