MP4 to MP3 Converter

Plenty of videos are really audio with a picture attached: a recorded lecture, a podcast episode posted as video, a concert filmed on a phone, a song with a static cover, an interview or a sermon. Keeping the whole MP4 for listening wastes storage and battery, and many players, car stereos and fitness watches will not play video files at all.

Extracting the sound turns that video into a small audio file you can listen to with the screen off, add to a playlist or load onto a device with limited storage. The MP3 is a fraction of the size of the video, because the picture is usually the biggest part of an MP4 by far.

It is also the simplest way to reuse a recording elsewhere. A talk filmed for a website can become a podcast episode, the music from a slideshow can go back into a playlist, and a recorded meeting can go to a transcription tool that only takes audio files.

MP3 is MPEG-1 Audio Layer III, standardized by ISO in 1993 as part of ISO/IEC 11172-3. Its age is its strength: every operating system, browser, phone and audio device made in the last two decades plays it. The audio inside an MP4 is usually AAC, a newer codec, and converting re-encodes it to MP3.

Because both are lossy, quality depends on the source and the bitrate. The preset of 192 kbps is high enough that music from a typical video sounds the same as in the original. Going higher rarely helps, since the MP3 cannot hold detail the video's own audio track already discarded.

Browsers are only part of the picture. Car stereos, older MP3 players, smart speakers and many fitness devices read MP3 and little else, while support for M4A and Ogg varies from model to model. If you do not know where the file will end up, MP3 is the safe choice. The Audio Converter can switch formats later without the video.

Sizes follow directly from the bitrate: kilobits per second times sixty seconds, divided by eight bits per byte, gives the size of one minute. A one-hour lecture at 128 kbps is therefore around 58 MB, small enough for any phone. Choose Mono under Channels for speech recordings if you want to halve the size at the lower bitrates.

When in doubt, keep the preset. It suits nearly everything people extract from videos.

You can convert up to 20 MP4 files at a time, each up to 95 MB, and every file gets the same settings. Use Start at and End at to skip an intro or keep a single song. Uploads are deleted after processing and the MP3s 30 minutes later, with no account to create.

For editing the sound in an audio program, an uncompressed file is the better start; MP4 to WAV makes one. Videos from an iPhone in MOV format are handled the same way on MOV to MP3, and every other source format is listed on the Video to Audio tool.