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WebM to MP4

Convert WebM videos, such as screen and webcam recordings or clips saved from the web, into H.264 MP4 that plays on iPhones, Windows, TVs and every editor. Pick the resolution and quality, see the estimated size, and convert right in your browser.

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Estimated size—
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What your browser can open and create

Can open (input)

    Can create (output)

      Checked live in this browser. Chrome, Edge and Safari can create H.264 MP4; Firefox and some Linux browsers cannot record MP4, so use one of the others for this conversion.

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      How to use the WebM to MP4

      1. Choose your WebM video by dropping it on the box or clicking Choose WEBM file.
      2. Check the output: MP4 (H.264 + AAC) is selected when your browser can create it.
      3. Set resolution, frame rate, quality and audio, and optionally a start and end time. The estimated size updates instantly.
      4. Press Convert to MP4 and keep the tab visible. Conversion runs in real time.
      5. Preview the result and press Download MP4.

      WebM and MP4 compared

      WebMMP4 (H.264 + AAC)
      Video codecsVP8, VP9, AV1H.264 (also HEVC, AV1 in newer files)
      Audio codecsOpus, VorbisAAC (also Opus, MP3)
      Made byBrowsers' recorders, web video sitesPhones, cameras, editors, most software
      Plays onBrowsers, Android, VLCPractically everything, including iPhone apps, Windows, TVs and game consoles
      Size at equal qualityVP9 and AV1 are 20 to 50% smaller than H.264Baseline

      Because WebM's video codecs are different from H.264, the conversion must decode and re-encode every frame; there is no lossless shortcut as there is for MOV to MP4.

      Choosing settings

      • Screen recordings: keep the original resolution, 30 fps and Balanced. Text stays sharp, and the MP4 is often smaller than the WebM.
      • Webcam clips and social media: 720p or 1080p at 30 fps, Balanced. Instagram, TikTok and WhatsApp re-compress uploads anyway.
      • Keep maximum detail: High quality or Match original bitrate at the original resolution.
      • Smallest file: 480p or 720p, Small file, 96 kbps audio.

      The estimate uses size = (video bitrate + audio bitrate) × seconds ÷ 8 plus about 2% for the container. Quality presets scale with the number of pixels per second: High is 0.12 bits per pixel per frame, Balanced 0.07 and Small 0.04, so 1280 × 720 at 30 fps on Balanced is about 1.9 Mbps, roughly 15 MB per minute with 128 kbps audio.

      Only need the sound?

      To save just the audio of a WebM video, use WebM to MP3, which decodes the soundtrack directly and is much faster than converting the whole video.

      Frequently asked questions

      How do I convert WebM to MP4?

      Choose your WebM video, keep MP4 (H.264 + AAC) as the output, adjust the resolution or quality if you like and press Convert to MP4. The video is re-encoded in your browser, then you can preview and download the MP4.

      Why convert WebM to MP4?

      WebM plays in browsers, but many phones, Apple apps, Windows editors, TVs and upload forms expect MP4 with H.264 video. Converting makes screen recordings and web clips easy to share and edit.

      Which browsers can convert WebM to MP4?

      Current Chrome and Edge on Windows, macOS and ChromeOS, and Safari on macOS and iPhone can record H.264 MP4. Firefox cannot create MP4 video and older Safari versions cannot open WebM, so use Chrome or Edge if your browser is not supported.

      Why does conversion take as long as the video?

      WebM uses VP8, VP9 or AV1 video, which MP4 players expect as H.264, so every frame must be re-encoded. The browser plays the video in a hidden player and records it with MediaRecorder in real time. Keep the tab visible so frames are not dropped.

      Will the quality drop?

      Re-encoding always loses a little detail. Use High quality or Match original bitrate and keep the original resolution to stay close to the source. For screen recordings, Balanced at the original resolution is usually indistinguishable.

      Is my video uploaded?

      No. The WebM file is decoded and encoded inside your browser tab, so private recordings never leave your device.

      My WebM recording shows no length. Can it be converted?

      Yes. Recordings made in a browser often have no duration in the file. The tool scans the file to find its real length before converting, and the MP4 has a proper duration.

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