Convert MP4 to MP3, Free
Upload your MP4 file and get a MP3 in seconds. No account, no watermark.
How to convert MP4 to MP3
Extracting audio from an MP4 video file lets you save music from a concert recording, pull commentary from a tutorial video, create a podcast episode from video footage, or archive just the audio portion of a large video file to save space. The audio track inside an MP4 is typically encoded as AAC, and BoltConverter extracts and saves it as a standard audio file.
BoltConverter strips the video data from your MP4 and extracts the audio stream on our servers. The output audio file can be downloaded in a universally compatible format. After the conversion, both the video and audio files are deleted from the server.
Upload your MP4 file
Click the upload area or drag your .mp4 video file onto the page.
Audio track is extracted
BoltConverter separates the audio stream from the video data on our servers and packages it as a downloadable audio file.
Download the audio file
Click Download to save the extracted audio to your device. The video data is discarded.
Frequently asked questions
What audio format is the output?
The output is typically an MP3 file, which is universally compatible with all devices and media players. The audio from the MP4 is re-encoded to MP3 if it is not already in that format.
Does the audio quality change?
The audio quality is largely preserved. When converting from AAC (the most common MP4 audio codec) to MP3, there may be a small, usually inaudible quality reduction because both are lossy formats.
Can I extract audio from a video that has multiple audio tracks?
BoltConverter extracts the primary audio track. If you need a specific secondary track, you may need a more advanced tool like FFmpeg.
Is there a file size limit?
MP4 files up to 500 MB are supported. For feature-length videos, consider extracting only the portion you need first.
Are my files stored on the server?
No. Both the uploaded MP4 and the extracted audio file are deleted from our servers immediately after you download the result.