How to convert MP4 to MP3

On any device, in the browser

1. Open the video. MP4, MOV, WebM and MKV files work, including iPhone and Android recordings.
2. Choose MP3. The first time, the page loads a small MP3 encoder. After that it encodes on your device.
3. Keep only a part, if you want. Tick Only save part of the sound, then drag the handles or type a start and end time.
4. Extract and download. Play the result on the page to check it, then download it.

This works the same on Windows, Mac, iPhone and Android, so it’s the simplest option if you just need the MP3. The sections below cover the built-in and free desktop routes too, for when you’d rather not use a website.

On Windows

Windows has no built-in way to save a video’s sound as MP3. Two free programs do it:

• VLC media player: choose Media › Convert / Save, add the video, click Convert / Save, pick the profile Audio - MP3, choose a destination file ending in .mp3 and click Start.
• FFmpeg, if you are comfortable with a command line. This drops the video (-vn) and encodes the sound as MP3 at 192 kbps:

ffmpeg -i video.mp4 -vn -b:a 192k audio.mp3

Both re-encode the sound, like any MP3 conversion. The browser method above needs no install.

On a Mac

Apple’s own apps can do it in two steps, with nothing to install:

1. Export the sound from QuickTime Player. Open the video, choose File › Export As › Audio Only. You get an M4A file with AAC sound, which already plays in most apps.
2. Turn the M4A into an MP3 with the Music app. In Music, open Settings › Files › Import Settings and choose MP3 Encoder. Add the M4A to your library, select it and choose File › Convert › Create MP3 Version.

The MP3 appears next to the original in your library. Set the import setting back afterwards if you import CDs. If an M4A is good enough for where it’s going, stop after the first step.

On an iPhone or iPad

iOS has no built-in MP3 converter. Open MP4 to MP3 in Safari instead:

1. Tap the box and choose Photo Library. Pick the video. To use a file you saved elsewhere, choose Choose File and browse in Files.
2. Choose MP3 and extract. Keep Safari open on the page until it finishes, especially for long videos.
3. Download. Safari saves the MP3 to Files, in the Downloads folder, where music, voice memo and editing apps can open it.

If you only need the sound to play on the phone itself, choose M4A instead: it is quicker, plays in every Apple app and can copy the sound out without any loss.

On Android

Android also has no system MP3 converter. Open the tool in Chrome, tap the box, pick the video from your gallery or Files, choose MP3, then extract and download. The MP3 lands in the Downloads folder. On older or low-memory phones, long videos take longer because the phone does the encoding.

Which bitrate to pick

The bitrate is how much data each second of sound gets. Higher sounds better and makes a bigger file. Sizes follow directly from it: kbps × 60 ÷ 8 gives kilobytes per minute, so 192 kbps is 192 × 60 ÷ 8 = 1,440 KB a minute.

A higher bitrate can’t add quality the video never had. Going above the quality of the video’s own sound only makes the file bigger, so for most phone videos 192 kbps is plenty and 128 kbps is fine for speech.

MP3 or M4A?

Most MP4 videos carry their sound as AAC. Saving it as M4A with “Same as the video” copies that sound out exactly, with no quality loss and in seconds. MP3 has to be re-encoded, which is a small loss you won’t usually hear at 160 kbps or more.

Pick MP3 when something specifically wants it: an old player, a car stereo, a website that only takes .mp3, or a ringtone app. Pick M4A otherwise. To change an existing audio file’s format later, use the audio converter; to shorten it, use Trim audio.

Common problems

• “This video has no sound track.” Some screen recordings and exported clips are saved without audio, so there’s nothing to extract.
• “Can’t decode the sound.” Some cameras record Dolby (AC-3) sound that browsers can’t read. VLC or FFmpeg can handle it.
• You only have a link. The tool converts files on your device, not YouTube or other links. Downloading from streaming sites is often against their terms.
• The preview doesn’t play. Some MKV files can be processed but not previewed in the browser. The extracted file is still fine.

Sources

• Apple Support: Export movies to other file formats using QuickTime Player on Mac. Audio Only exports an MPEG-4 audio file with AAC sound
• Apple Support: Convert an M4A file to MP3 on Mac. MP3 Encoder import setting and Create MP3 Version
• Apple Support: Convert music file formats in Music on Mac