WebM to MP4 Converter — Free, No Upload

Convert WebM recordings and clips to widely compatible MP4 (H.264) without uploading them. Free, no sign-up, and your files never leave your device.

Free, with no sign-up and no watermark. The file is processed in your browser and never uploaded.

Convert WebM videos to MP4 right in your browser. When the original codec already fits MP4 and you keep the original resolution, the video is copied without re-encoding — instant and lossless. Otherwise it's re-encoded with your browser's own encoder.

Need a different format? The Video Converter handles MP4, WebM, MOV and MKV in any direction.

Step by step

  1. Add your WebM file: Drop the video onto the upload area or click to browse. Its length, resolution, frame rate and codecs appear underneath.
  2. Check the output: Convert to is already set to MP4. Leave Video codec on Automatic for the most compatible result, or pick a specific codec.
  3. Choose quality and size: Keep Quality on High and Resolution on Original for the best result, or lower them for a smaller file. Lower resolutions never upscale.
  4. Convert: Click Convert to MP4. A progress bar shows how far along it is, with a Cancel button.
  5. Save: The MP4 file downloads automatically and a preview appears so you can check it.

Handy for

Play anywhere

Turn a file that won't open on a TV, phone or editor into a format it accepts.

Web pages

Produce a compact file for embedding on a site.

Editing software

Convert clips into a format your editor imports cleanly.

Sharing

Send a format the other person can open without installing anything.

Good to know

  • MP4 with H.264 is the safest choice for sharing — it plays on virtually every device.

  • To make the file smaller as well, use Compress Video — it lets you pick a target size in MB.

  • Only need the sound? Use Extract Audio from Video.

Questions

Is my video uploaded anywhere?

No. The video is read, decoded and re-encoded inside your browser using its built-in WebCodecs encoders. Nothing is sent to a server, so private recordings stay on your device.

Which file types can I use?

MP4, MOV, M4V, WebM, MKV and MPEG-TS videos. Older formats such as AVI, WMV and FLV can't be read in the browser — you'll see a clear message if you try one.

Will I lose quality?

Not when the video can be copied as-is (Automatic codec, Original resolution, High quality, compatible codec). When re-encoding is needed, High quality keeps the result visually very close to the original.

Which browsers work?

Recent Chrome, Edge and Safari (17 or newer) work best. Firefox can read most files but may lack some encoders, such as H.264 — if a format isn't available, the tool says so before you start. Phones work too, but long or 4K videos can run out of memory.

How long does it take?

Copy-only jobs (changing the container, muting, fast rotation, most trims) take seconds. Re-encoding runs at roughly real time or faster on a modern laptop; 4K and long videos take longer. A progress bar shows how far along it is, and you can cancel at any time.

More Video Tools tools

  • MOV to MP4 — Convert MOV videos from iPhone, Mac or cameras to MP4 — often instantly, with no quality loss.
  • MKV to MP4 — Convert MKV (Matroska) videos to MP4 so they play on phones, TVs and editors.
  • Compress Video — Reduce video file size with quality presets or an exact target size in MB, without uploading the file.
  • Trim Video — Trim the beginning or end of a video with a preview and exact start/end times, without re-encoding by default.
  • Video to GIF — Turn a short part of any video into an animated GIF, choosing frame rate, width and colours.
  • GIF to MP4 — Convert animated GIFs into small MP4 or WebM videos that can be shared anywhere.

All Video Tools tools