Convert an Audio File to MP3

Which MP3 quality to choose: 128, 192 or 320 kbps?

The bitrate sets both the quality and the file size. A 128 kbps MP3 takes up about 0.96 MB per minute, 192 kbps about 1.44 MB, and 320 kbps about 2.4 MB. A 3-minute song is therefore roughly 2.9 MB, 4.3 MB or 7.2 MB depending on the setting. For voice (voice memo, lecture, meeting, WhatsApp message), 128 kbps is plenty. For music, 192 kbps is a good compromise and 320 kbps is the maximum of the MP3 format. Note that choosing 320 kbps for a poor-quality recording doesn't improve it: it just makes the file bigger.

M4A, WAV, OPUS, AMR: why convert to MP3?

Each device records in its own format. The iPhone Voice Memos app creates M4A files, WhatsApp records voice messages in OPUS (sometimes with an .ogg extension), older phones and some voice recorders use AMR, and a recorder or editing software often produces WAV, which takes up about 10 MB per minute at CD quality. MP3, on the other hand, plays on almost anything: car stereos, old MP3 players, TVs, editing software, or websites that only accept that format. Converting to MP3 avoids unplayable files and, starting from a WAV, cuts the size by five to ten times.

MP3, WAV or M4A: which output format?

MP3 is a lossy compressed format: part of the audio information is removed to save space, inaudibly at a good bitrate, but permanently. So keep your original FLAC or WAV file if you want the best possible quality. Choose WAV if editing software or a platform requires an uncompressed file: no further loss, but a large file. M4A works well on Apple devices. To extract the audio from a video, use “Convert MP4 to MP3”; to get the text of a recording, “Transcribe Audio to Text”.