You Have a Video. You Only Need the Audio.
A lecture recording you want to listen to while driving. A music video you want on your phone as audio. A podcast that was recorded as a video call. A voice memo your phone saved as MP4. A webinar you want to turn into a podcast episode.
The video part is useless to you. You just need the sound.
MP4 to MP3 is the most common file conversion on the internet, and it takes about 10 seconds.
How to Do It
- Go to FluidConvert's MP4 to MP3 converter
- Upload your MP4 file (or drag and drop it)
- Click Convert Now
- Download your MP3
That's it. The audio track is extracted from the video and saved as a standalone MP3 file. The video data is discarded.
What Happens During Conversion
An MP4 file is a container — it holds a video stream and an audio stream as separate tracks inside one file. When you convert to MP3, the tool:
- Opens the MP4 container
- Finds the audio track (usually encoded in AAC)
- Decodes the AAC audio
- Re-encodes it as MP3
- Discards the video track entirely
The result is an MP3 file that's typically 90-95% smaller than the original MP4. A 500MB video might produce a 20-40MB MP3 depending on the audio bitrate.
Does It Lose Quality?
Technically, yes — but practically, you won't hear it.
The audio in most MP4 files is already compressed (usually AAC at 128-256 kbps). Converting to MP3 is transcoding from one lossy format to another, which introduces a tiny amount of additional compression. At 192 kbps or higher, this is inaudible on normal speakers, earbuds, and car stereos.
The only time quality matters is if you're extracting audio for professional music production — in which case you'd want WAV (lossless) instead of MP3. For listening, podcasts, presentations, and content repurposing, MP3 is perfect.
What Bitrate Should You Use?
Bitrate controls the tradeoff between file size and audio quality:
Rule of thumb: If it's speech, 128 kbps is fine. If it's music, use 192 or higher.
What About Other Audio Formats?
MP3 isn't the only option. Here's when you might want something else:
WAV — Uncompressed, lossless. Use this if you need the raw audio for editing in GarageBand, Audacity, or a DAW. Files are huge (10x larger than MP3) but have zero quality loss. Convert MP4 to WAV
AAC/M4A — The audio codec already inside most MP4 files. Better quality than MP3 at the same bitrate. Use this if you're staying in the Apple ecosystem (iPhone, iTunes, Apple Music). Convert MP4 to AAC
FLAC — Compressed but lossless. About 50% the size of WAV with identical quality. Use this for archiving music or audio you might edit later. Convert MP4 to FLAC
OGG — Open source alternative to MP3. Better quality at lower bitrates. Used by Spotify internally and supported by most modern players.
For 95% of people, MP3 is the right choice. It plays on literally everything — every phone, every computer, every car stereo, every Bluetooth speaker, every audio app ever made.
Common Questions
Can I extract audio from a YouTube video?
FluidConvert converts files you upload — it doesn't download from URLs. If you've already downloaded an MP4 from a legitimate source, you can extract the audio from it. We don't support direct URL-to-MP3 conversion.
Will subtitles or chapters transfer?
No. MP3 is a pure audio format. Subtitles (which are text) and chapter markers are discarded during conversion. If you need chapters in your audio, some podcast apps support MP3 chapter markers, but that requires a separate tool.
Can I convert just part of the video to MP3?
The MP4 to MP3 converter extracts the full audio track. If you only need a portion, use the Video Trimmer first to cut the video to the section you want, then convert that trimmed clip to MP3.
Does it work with other video formats?
Yes. FluidConvert extracts audio from any video format — MP4, MOV, AVI, MKV, WEBM, WMV, FLV. The process is the same regardless of the container format. Try the Video Converter for other formats.
Can I convert multiple files at once?
Currently you upload and convert one file at a time. For batch conversions, process them sequentially — each one takes just a few seconds.
Extract Your Audio
MP4 to MP3 — the most universal audio format, plays everywhere
MP4 to WAV — lossless, for editing and production
MP4 to AAC — better quality per bitrate, great for Apple devices
All free, all instant, files encrypted and auto-deleted after conversion.