Free · No upload · No sign-up
Convert WebM to MP4
Turn WebM into MP4 (H.264 + AAC) for universal playback on iOS, Premiere, FCP, and every social platform — in your browser.
WebMMP4
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Drop your .webm file here
Converted to MP4 in your browser.
Why this tool
Universal playback
Output is MP4 (H.264 + AAC, +faststart) — plays on every modern device, editor, and social app that chokes on WebM.
Private by default
Conversion runs in your browser tab via ffmpeg.wasm. Your WebM never leaves your device.
Editor-friendly
H.264 + AAC in an MP4 container is the lingua franca of video editing. Drop the output straight into Premiere / FCP / Resolve.
How to convert WebM to MP4
- 1Drop your .webm file above.
- 2Pick a quality preset. Balanced is the safe default.
- 3Click Convert. The progress bar shows live ETA.
- 4Download the .mp4 file — ready for iPhone, Premiere, Instagram, etc.
Frequently asked questions
- Why convert WebM to MP4?
- Most video editors, iPhones, and many social platforms don't import or play WebM smoothly. MP4 (H.264 + AAC) is the universal fallback that just works everywhere.
- Is it lossless?
- No — we re-encode with H.264. High preset is visually very close to the source; Balanced is fine for 1080p social uploads. Keep the original WebM if you need a lossless archive.
- Does Clapr upload my file?
- No. Conversion runs in your browser via ffmpeg.wasm. Nothing is uploaded.
- How long does it take?
- A 3-minute 1080p clip typically finishes in under a minute on a modern laptop. Speed depends on CPU cores and source bitrate.
- Will transparency (alpha) be preserved?
- No. MP4 (H.264) does not support alpha. Transparent WebM frames become opaque black on conversion.
- What's the max file size?
- Up to 4GB in-browser. Memory usage is roughly 2× file size; low-RAM devices should trim large clips first.