MP4 to MP3 converter
Keep the sound, drop the picture. The voice-over, the interview, the song you played — as an MP3 that plays anywhere.
Everything happens inside your browser, using your own computer’s memory. Your file is never uploaded, never stored, and nothing is sent to us — so there is no limit on how often you use this.
How converting MP4 to MP3 works
At a glance
- Converts
- MP4 to MP3
- Runs on
- Your computer, inside this tab (WebAssembly)
- Fastest
- M4A — the sound is copied out untouched, in seconds
- Most compatible
- MP3 — plays on every device, about 1.4 MB a minute
- For editing
- WAV (uncompressed) or FLAC (lossless, smaller)
How it works
MP3 is the format every player, phone and car stereo reads. Pulling it out of a video is the quickest way to reuse a voice-over, send a recording to someone to listen to, or keep a track for editing.
The picture is discarded, so the MP3 is a small fraction of the video's size.
Step by step
- Drop the fileA video, or an audio file you want in another format. Nothing uploads; it opens in this tab.
- Pick the formatMP3 to listen or share, M4A to keep the original untouched, WAV or FLAC to edit.
- ExtractM4A usually takes seconds. MP3, WAV and FLAC re-encode the sound, which is still quick — sound is far lighter than picture.
- DownloadThe file stays in this browser until you press Delete.
Which setting for which job
| If you are… | Choose |
|---|---|
| Sending a voice note or recording for someone to listen to | MP3 |
| Keeping the original sound exactly as it was recorded | M4A — copied, not re-encoded |
| Cleaning up or mixing the sound in an audio editor | WAV |
| Archiving without losing anything, at a smaller size | FLAC |
| Reusing a voice-over under a new video | M4A or WAV |
| Putting a song you liked into your own post | Do not — music in a video is usually someone else's copyright |
Under the hood
The technical detail, for anyone who wants to know exactly what happens to their file. Each line first says it plainly.
Demuxing
Taking one track out of a container.
The video stream is discarded (-vn) and only the audio stream is written to the new file. No part of the picture is decoded.
M4A: stream copy
The original sound, byte for byte.
Phones record AAC, and -c:a copy moves that track into an M4A file untouched: no quality change, and done in seconds. If the track turns out not to be AAC, it is re-encoded as AAC at 192 kbps instead.
MP3: LAME at -q:a 2
High-quality variable bit rate.
LAME's V2 setting varies the bit rate with the sound — more for complex passages, less for quiet ones — averaging about 190 kbps. Indistinguishable from the original for speech and most music on a phone.
WAV: 16-bit PCM
No compression at all.
Every sample stored as a 16-bit number. For 48 kHz stereo that is 48,000 × 16 × 2 = 1,536 kbps, about 11.5 MB a minute. Audio editors start from this so nothing is lost before the edit.
FLAC
Lossless, but smaller than WAV.
Compressed like a zip file is: it decodes back to exactly the same samples. Typically around half the size of WAV, depending on the sound.
Sample rate
Kept as recorded.
The sound keeps the sample rate it was recorded at — 48 kHz on most phones — so nothing is resampled.
If something goes wrong
| What you see | Why | What to do |
|---|---|---|
| “This video has no sound track” | The file genuinely has no audio stream — often a screen recording made without sound, or a clip already muted. | Check the microphone was not muted or covered when you filmed. |
| M4A said it was converting instead | The sound in this video is not AAC, so it cannot be copied into an M4A as it is. | Nothing to do — it is re-encoded as AAC at 192 kbps automatically. |
| The WAV is enormous | WAV is uncompressed: about 11.5 MB for every minute of 48 kHz stereo. | Use FLAC for the same quality at about half the size, or MP3 for listening. |
| I only want part of the sound | Extracting always takes the whole track. | Trim the video to the part you want first, then extract the sound from the trimmed file. |
Privacy: your file stays on your computer
Recordings often carry voices, names and conversations. Extracting the sound in your browser means none of it is sent anywhere to be processed.
- What your browser downloads
- The page — and, the first time you use a video tool, the video engine: about 32 MB, then kept in your browser's cache.
- What it sends to us
- Nothing. There is no upload step, no copy on our servers and no account. The work happens in your computer's memory.
- How we know
- Our automated tests run every tool while recording every network request the page makes. A single upload fails the test.
- Where the result lives
- In this browser only, until you press Delete. A finished file is still here if you close the tab and come back; a job still running stops when the tab closes.
Questions
What quality is the MP3?
High variable bit rate (about 190 kbps) — indistinguishable from the original for speech and music on a phone.
Is my file uploaded?
No. The conversion runs inside your browser, using your own computer's memory. The file never leaves your device.
Which format should I pick?
MP3 to listen or share. M4A to keep the original untouched. WAV or FLAC to edit in an audio program.
Does it lose quality?
M4A is copied and loses nothing. WAV and FLAC are lossless. MP3 is compressed, at a high setting you will not hear on a phone.
Can I use the sound from someone else's video?
Only if you have the rights. Music in particular is usually owned by someone, and platforms mute or remove posts that use it without a licence.
Can I convert an audio file, not a video?
Yes — drop an audio file and pick the format you want.
A tool makes a file fit. It does not make people watch to the end — that is the hook, the order of the shots, the captions and the music. See how Ruzz does it.
Other conversions
Other free tools
Compress video
Too big to upload, email or text? Make it small enough, without it looking bad. Takes a few minutes.
Convert format
Will not play or upload? Turn an iPhone MOV/HEVC, WebM or MKV into an MP4. Often seconds, with no quality loss.
Crop to 9:16
Turn a landscape or square video into a vertical short for Reels, TikTok and Shorts.
Trim video
Cut the dead air off the start and end, or keep just the 30 seconds that matter.
Grab a cover frame
Pick any moment and save it as a vertical cover image.
Join clips
Filmed it in three takes? Put them end to end in one video — different shapes and silent clips are fine.
Video to GIF
Turn a moment into a GIF with real colours, not the grainy web palette.
Compress image
Shrink and resize a photo to JPG, WebP or PNG. Instant.
Change speed
Slow motion or sped up, from 0.5× to 2×, with voices at their own pitch.
Remove sound
Take the audio off a video in seconds, picture untouched — then add a trending sound in the app.
Resize video
Exactly 1080×1920, 1080×1350, 1080×1080 or 1920×1080 — the size each platform asks for.