Step 1: Supply your MP4 files using the button above or by haul and lay.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Get your converted WebM files.
MP4 to WebM Conversion FAQ
Will resolution and frame rate be preserved in the WEBM?
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Yes. MP4 → WEBM keeps resolution, frame rate, and aspect ratio unchanged by default. To change them, use the Resize or Speed tool on the result.
Is the MP4 to WEBM conversion reversible?
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You can convert the WEBM back to MP4 on this site. If either format involved is lossy, the round-trip is not bit-perfect even though it is visually or audibly close.
Is WEBM worth targeting for a video on a web page?
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For a page you control, yes. WEBM was built for exactly that job — it plays inline in every current browser with no plugin, no licence fee and no patent exposure, which is why it became the default for embedded and background video. Away from the browser it is the weaker choice: editing software, phone galleries and televisions largely ignore it, so it is a delivery format rather than a storage one. Keep the master in something else and publish this. WebM plays natively in every modern browser with no plugin, no licence fee and no patent exposure, which makes it the default for web-embedded video.
Both MP4 and WEBM are modern containers — which should I actually keep?
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Keep whichever matches where the file is going, because neither is better in the abstract. One of these two is built for playback compatibility and the other for holding everything a file might contain, and they trade against each other exactly along that line. The pragmatic answer for most libraries is to archive in the feature-rich container and export to the compatible one on demand. MP4 is the safest possible delivery target — every phone, browser, console, editor and Smart TV built in the last decade plays it without extra software.
Is there a file-size limit when converting MP4 to WEBM?
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Free conversions have a size limit per file, set by the type of file, and the page tells you when a file is over it. A paid plan removes that limit, so much larger files can be converted.
Can I batch-convert several MP4 files to WEBM at once?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
What happens to my MP4 files after the conversion?
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Uploaded files are processed on our own conversion servers, nobody looks at them, and they are not shared. The upload and the converted file are both deleted automatically about 24 hours after the conversion, which leaves time to download the result. See /privacy/ for the full policy.
Will my WEBM play on phones, tablets, and TVs?
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Yes — WEBM uses modern codecs that play natively on iOS, Android, Smart TVs, game consoles, and every modern browser.
Do I need to install software to convert MP4 to WEBM?
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No. The converter runs entirely in your browser plus our cloud — no plugin, no install, no admin rights. It works on Windows, macOS, Linux, ChromeOS, iOS, and Android.
Do I need an account to convert MP4 to WEBM?
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Yes. One conversion an hour is free, with no account needed, for a file within the free size limit. A paid plan removes the hourly limit and the size limit, and lets you add several files to one job.
Is there an API for MP4 to WEBM conversion?
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Yes. Every conversion this site offers is also exposed via a JSON API — see /api/ for endpoints, authentication, and rate limits. MP4 to WEBM is one of the supported pairs.
What if my MP4 fails to convert to WEBM?
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Failures are usually caused by corrupted source files or unsupported MP4 variants. Re-export from the original app and try again; if it still fails, the contact page forwards the file to support so we can diagnose.
