WebM to MP4 Converter

Convert WebM (.webm) to MP4 right in your browser. No upload.

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Connected — privacy mode available

You don't need the internet. Disconnect and watch the tool work.

Online

🔒 Verify the privacy claim yourself

Simplest way to confirm your videos never leave this device:

Disconnect from the internet.

Turn off your Wi-Fi → conversion keeps working. The banner up top turns green.

Note: a small one-time load happens on first use. After that, you can work fully offline.

or drop a WebM file here

Accepts WebM (.webm) — including clips downloaded from Twitter, Reddit, and other web sources

Output: MP4 container with H.264 video + AAC audio — the most compatible combination, playable everywhere from old phones to modern browsers.
Loading conversion engine (~30 MB) — first time only…

Why convert in your browser?

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Your video never leaves your computer

Conversion runs on your computer — not on someone else's server. Zero uploads.

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Lossless remux when possible

If your WebM file already contains H.264 video, we just rewrap it into an MP4 container — no re-encoding, no quality loss, near-instant.

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VP9 + VP8 source supported

Google's WebM codecs are transcoded to H.264 + AAC, making your clips playable on iOS, QuickTime, and any social app that rejects WebM.

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No watermark, no signup, no caps

CloudConvert caps free users at 10 conversions/day. Zamzar limits at 50 MB. VEED watermarks. We don't do any of that.

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No file size limit

Drop a 4 GB drone clip if you want. The only limit is your device's available memory — there's no upload step to choke on.

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Works offline after first visit

The engine downloads once, then runs forever. Turn off Wi-Fi to verify — conversion keeps working.

How we compare on "webm to mp4"

This tool CloudConvert Zamzar FreeConvert VEED.io
Video stays on your computer✓ VerifiableUploadsUploadsUploadsUploads
Free file-size capNone1 GB50 MB1 GB1 GB
Conversions per day (free)Unlimited10 / day2 / dayUnlimited—
Watermark on free tierNeverNoneNoneNone"VEED" on free
Lossless remux (H.264 source)✓ AutomaticRe-encodesRe-encodesRe-encodesRe-encodes
Signup requiredNeverNoFor >2 / dayNoFor pro

Common questions

Why won't my .webm play on iPhone or in QuickTime?

WebM uses VP8 or VP9 video codecs — Google's open formats — which Apple has historically refused to support. iOS Safari now plays VP9, but Photos, AirDrop, and most mobile editing apps don't. Converting to MP4 (H.264 + AAC) makes the file work everywhere.

How long does conversion take?

If your source already contains H.264 (older iPhones, most QuickTime recordings), conversion is a fast remux — usually under a second. For HEVC sources requiring transcode, expect 10–60 seconds per minute of footage depending on resolution and CPU.

Does my video get uploaded to your server?

No. Conversion runs entirely in your browser. Disconnect from Wi-Fi after the page loads to verify — the converter keeps working.

Is there a watermark or file-size limit?

Neither. Plain .mp4 output. No backend means no caps — the only limit is your device's available memory.

Will I lose quality?

If the source is H.264, we remux (copy the video stream into MP4 without re-encoding) — 100% lossless. For HEVC and other codecs, we transcode at CRF 18 by default, which is visually lossless for nearly all viewers.

Turn off your Wi-Fi. It still works.

That's how you know nothing leaves your computer.

CloudConvert, Zamzar, FreeConvert, VEED — they all send your video to a server. We don't. Conversion runs on your CPU, in your browser, via the same ffmpeg engine VLC and YouTube use.

Try it yourself ↑

Works on every device you use

iOS, Android, macOS, Windows, or any modern browser — same tool, same code, same privacy.

iOS
Android
macOS
Windows
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