Convert WAV to MP3

WAV is uncompressed audio. It is what recorders, DAWs, Windows Voice Recorder and many dictation devices produce, and it is enormous: CD-quality stereo takes about 10 MB per minute, so a one-hour interview is over 600 MB. That is too big for email, many upload forms, most transcription services with size caps, and phones with little free space. MP3 stores the same recording in a fraction of the space.

The only decision is the bitrate. 192 kbps is transparent for most music and gives files around one seventh of the WAV size; 320 kbps is the MP3 maximum for archiving music you care about; 128 kbps is plenty for podcasts; 64 kbps keeps speech clear and makes an hour of talk under 30 MB. The conversion uses the LAME MP3 encoder inside FFmpeg, running as WebAssembly in your browser, so private recordings such as meetings, interviews and medical dictation are never uploaded anywhere.

Metadata chunks in the WAV (such as broadcast-wave descriptions) are not copied. 24-bit and 32-bit float WAV files, and WAV with sample rates other than 44.1 kHz, are all accepted; the MP3 keeps the original sample rate where MP3 allows it. Files up to 500 MB can be converted.