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MP4 to WebM Converter

Convert MP4 to WebM VP9 - 40% smaller than MP4 for websites. Private, no upload. Hardware accelerated when possible. Compress video for website background and fast loading.

🔒 No upload⚡ Fast WebMFree forever
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Drop MP4 file here or click to browse
MP4 → WebM · Private · Max 1GB

How to convert MP4 to WebM in 3 steps

  1. Drop your MP4 file — File stays on device, never uploaded. Works offline after first load.
  2. We auto-select WebM — For mp4-to-webm, we pre-select WebM output. You can change quality, resolution, rotate.
  3. Convert & download — Click Convert. Fast remux uses -c copy when possible (instant), otherwise H.264 + AAC re-encode.

Why private matters: Wedding videos, work recordings, voice memos — uploading leaks them. Here, ffmpeg.wasm runs locally. No server copy.

FAQ: MP4 to WebM

Is MP4 to WebM private?

Yes. ffmpeg.wasm runs in your browser tab. No upload endpoint exists. Your file never leaves your computer.

Is it free? Watermark?

Free forever, no watermark, no account. Supported by ads after you click Accept.

Max file size?

Best under 500MB. Hard limit 1GB. For larger, use desktop Handbrake/Shutter Encoder.

Will quality drop?

If we can fast-remux (same codec, just changing container), no loss and instant. If we must re-encode (e.g., MP4→WebM with different codec), we use CRF 23 (Balanced) — visually lossless for most.

Other converters: MP4 to MP3 · MOV to MP4 · MP4 to GIF · Remove Audio · Compress Video
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