WebM to MP3 Converter
Extract the audio from a WebM video as MP3 — without uploading the video. WebM is the default format for OBS screen recordings, Discord voice messages, many video downloader outputs, and a lot of WebRTC-recorded files. The audio inside is usually Opus (high quality, tight compression), which every modern browser decodes natively. We extract just the audio track and re-encode to MP3 for universal compatibility.
-
Stays on your device
Your audio is decoded into your browser's memory by the Web Audio API, re-encoded by a JavaScript library running in the same tab, and the result goes straight to your downloads. No upload, no log, no third party. Sensitive recordings, voice memos, copyrighted tracks — none of it leaves your machine.
-
WebM → MP3 done right
WebM is the open-source video container that Google promoted as a royalty-free alternative to MP4. Audio is usually Opus (newer files) or Vorbis (older). Both are open codecs and both are natively supported in Chrome, Firefox, Edge, and Safari 14.1+. We pull out just the audio and re-encode to MP3, which plays everywhere from car stereos to old phones to non-browser apps that don't know what Opus is.
-
Quality control
Pick the MP3 bitrate that matches your use case — 128 kbps for podcasts and voice (smaller files), 192 kbps for music (our default, near-CD quality), or 320 kbps for archival (best fidelity, largest files).
Frequently asked questions
Does my audio ever leave my device?
No. The conversion runs entirely in your browser. We decode your file using the Web Audio API and re-encode it using a JavaScript encoder library, all in your browser tab. Open DevTools while you convert — you'll see zero traffic carrying your audio.
Is there a file size limit?
No fixed limit from us. The real ceiling is your device's memory: decoded audio sits in RAM as raw PCM, which is roughly 10 MB per minute of stereo audio at 44.1 kHz. A typical 5-minute song needs about 50 MB of working memory — fine on any modern phone or laptop. Hour-long podcasts may struggle on older devices.
Will the conversion change the audio quality?
MP3 is a lossy format, so encoding to MP3 always involves some quality loss compared to the source. At 192 kbps (our default), the difference is inaudible to most listeners on most playback hardware. WAV is lossless — if you're converting TO WAV, the output is bit-identical to what your source decoded into. If you're converting FROM a lossy source (MP3, M4A), the WAV won't be higher quality than the source — it'll just be uncompressed.
How long does conversion take?
Decoding is near-instant. Encoding speed depends on output format: WAV is essentially instant (just writing bytes). MP3 takes about 1 second of compute per 10 seconds of audio on a modern laptop — so a 5-minute song encodes in roughly 30 seconds. Phones are slower; expect 2-3x longer. Progress is shown live as the encoder works.
Does this work on mobile?
Yes. Tap the drop zone to open the file picker, choose your audio file, hit Convert. The result downloads to your device's standard download location. iOS users: the file lands in the Files app under Downloads.
What about ID3 tags (artist, album, song title)?
Original ID3 tags are not preserved in v1 — the encoded file gets no metadata. The audio itself is preserved exactly. If you need to keep artist/album/title info, you'll want to re-tag the output with a tool like MP3Tag (Windows) or Kid3 (cross-platform) after converting.
Where do WebM files usually come from?
Common sources: OBS Studio screen recordings, Discord voice messages saved to disk, output from many youtube-dl-style downloaders (which prefer WebM for higher quality at smaller file sizes), browser-based screen recording tools (Loom and others sometimes), files saved from WebRTC video calls, and old YouTube downloads. Any of these will work as input here.
Why convert WebM audio to MP3 — isn't Opus better?
Opus is technically the better codec — smaller files at higher quality. But MP3 is universal: car stereos play it, every phone plays it, old MP3 players and Bluetooth speakers play it, and every app that handles audio handles MP3. WebM/Opus playback is well-supported in modern browsers but spotty everywhere else. Converting to MP3 trades a tiny bit of audio quality for a huge gain in compatibility.
Will Vorbis (older WebM) work too?
Yes. The browser's audio decoder handles both Opus (newer WebM files) and Vorbis (older WebM files) transparently. We don't need to know which codec is inside; the browser figures it out. Output MP3 is identical in either case.
Will the audio quality stay the same?
Close. The browser decodes the source audio (Opus or Vorbis) to uncompressed PCM, then we re-encode that to MP3 at your chosen bitrate (default 192 kbps — close to transparent for most listeners). At 320 kbps the difference is inaudible for almost everyone. Going from a lossy codec to PCM to another lossy codec is technically two lossy steps, but the perceptual loss is small. If you want lossless output for archival, convert to WAV instead.
What about WebM video frames — what happens to those?
Nothing — they're never decoded. The audio extraction asks the browser for just the audio track. The video data sits unused in the source file. This is why the conversion is fast: even a long 4K WebM finishes in well under a minute on a normal laptop.
Why not use Safari for this?
Safari only added WebM playback support in Safari 14.1 (2021). Older macOS / iOS versions can't decode WebM at all, so this tool won't work there. Update Safari to current, or use Chrome / Firefox / Edge on the same machine — they've supported WebM for over a decade.