MP4 to WAV: Extract Audio from Video Online, Free

MP4 is a video container: it bundles a picture track and an audio track together. Most of the time that's exactly what you want, but sometimes only the sound matters — a phone recording of a lecture, a screen capture of a webinar, a downloaded video whose voiceover or music you need on its own. Rather than keeping the whole video around just to hear the audio, you can pull the audio track out into its own file. That gives you something you can drop straight into an audio editor, a podcast timeline, or a DAW project without dragging video playback along for the ride. The MP4 stays untouched — this just copies out the sound that's already inside it.

WAV stores audio as uncompressed, lossless PCM data. It opens in every audio editor and DAW without any decoding step, and because nothing was thrown away to shrink the file, it's the safer starting point if you plan to edit further — cleaning up dialogue, layering the extracted track under a podcast intro, or remixing a music bed. That matters because the audio inside an MP4 is usually already compressed with some codec; converting to WAV doesn't undo that, but it does stop you from stacking a second round of lossy compression on top when you re-export. If you just want to listen to the result or share it as-is, MP3 is the better choice — smaller file, no editing overhead. This tool's sibling, convert-mp4-to-mp3, covers that case.

The converter runs ffmpeg.wasm — a build of the ffmpeg audio/video engine compiled to WebAssembly — directly inside your browser tab. When you pick an MP4, it's read and processed on your own machine; nothing is uploaded to a server. That means no account, no waiting on a queue, and no watermark stamped on the output. It also means your file never leaves your device, which matters if the video contains anything private, like a recorded meeting or a personal video. Once processing finishes, the WAV file is handed back to you as a normal download. Because everything happens client-side, there's no server-side storage to worry about and no cleanup step needed afterward.

Drop in an MP4 and the tool extracts its audio track and re-saves it as PCM WAV — the video portion is discarded, only the sound comes out the other end. WAV files are larger than the compressed audio inside the MP4, since PCM stores every sample rather than encoding it down, so expect the download to be noticeably bigger than the source video's audio footprint. Processing time depends on the length of the video and your device's power, since the work happens in your browser rather than on a remote server. There's no length restriction beyond what your browser can comfortably handle, and no signup step between choosing a file and getting your WAV.

Say you've got a screen recording or a phone video with a voiceover you want to reuse — maybe as the spoken track under a podcast episode, or as source material for a music remix. Pulling it out as WAV instead of MP3 means when you open it in your editor or DAW, you're working with the cleanest version of that audio available from the MP4, with no extra compression pass added by the extraction step itself. That gives your editing — noise reduction, EQ, trimming, layering other tracks — the most headroom to work with. Once editing is done, you'll typically export the finished piece to whatever compressed format fits its final destination; the WAV stage is just the working copy in between.

Desktop tools like ffmpeg (command line) or Audacity (import video, export audio) can do the same extraction, and full video editors typically let you export an audio-only track too. Those routes work well if you're already set up with the software, but they mean installing something, learning a command or interface, and moving the file to and from that program. A browser-based converter skips all of that: open the page, choose the file, get the WAV back, all in one tab. If MP3 output fits your case better than WAV, the same site's convert-mp4-to-mp3 tool handles that conversion the same way — no upload, no install.