MP4 to MP3 Converter

Convert MP4 to MP3 without uploading

An MP4 file usually holds both a video track and an audio track. When you only need the sound, for example a recorded lecture, an interview, a music performance or a voice memo filmed on your phone, carrying the full video around wastes storage and is awkward to play in a car or on a music player. This MP4 to MP3 converter drops the picture, keeps the soundtrack and encodes it as an MP3 that plays on practically every device. Everything happens in your browser with ffmpeg.wasm, so private recordings are never sent to a server and there is no queue, account or watermark.

Bitrate, quality and file size

The audio inside most MP4 files is AAC, which is already compressed, so the MP3 is a second lossy encode. Choosing a sensible bitrate keeps the result transparent. Speech sounds clear at 128 kbps and produces small files that are ideal for transcripts and podcasts. 192 kbps is a safe default for mixed content, while 256 or 320 kbps preserves the most detail for music. Higher bitrates cannot add quality that the original video did not contain, but they avoid losing more. Title and artist tags are copied across when the MP4 contains them.

Tips for large videos and batches

Because the video is processed in memory, very long or high-resolution files need free RAM; close other heavy tabs before converting a feature-length recording. You can add several MP4 files at once, preview each MP3 in the built-in player and download them all together. If your video is in another container such as MOV, MKV, AVI or WebM, use the Video to MP3 converter instead, and if you need to cut out only part of the track, trim the MP3 afterwards with the audio cutter.