Convert WAV to MP3

How to convert WAV to MP3

1. 1

   Add your WAV files

   WAV, BWF, RF64 and AIFF, up to 200 MB each and twenty at a time.

2. 2

   Choose a bitrate

   192 kbps for music, 320 to stay close to the source, 64 to 96 for speech recordings.

3. 3

   Click Convert and download

   The result is a standard MP3 with a Xing header, so players show the right length and seek correctly.

Where the ten-fold saving comes from

A WAV file stores every sample exactly as it was captured: at CD quality that is 1,411 kilobits for every second of stereo sound, and nothing about the file is compressed. MP3 throws away the parts of the signal that a listener is very unlikely to notice: frequencies masked by louder ones nearby, detail above the range most people hear, and the difference between channels where it does not matter. At 192 kbps that is roughly a seventh of the data; at 128 kbps a eleventh. The saving is real and the loss, at sensible bitrates, is hard to hear on ordinary equipment. What it is not is reversible, which is why converting back to WAV afterwards restores the size but not the sound.

Recordings, not just music

WAV is what almost every recorder writes: field recorders, dictation apps, interview setups, broadcast systems. Those files are often enormous relative to what they contain: an hour of stereo speech is over 600 MB as WAV and about 27 MB as a 64 kbps MP3, with no meaningful loss of intelligibility because speech carries nothing above a few kilohertz worth protecting. If the recording is a single voice, converting it to mono first halves the size again before the bitrate is even chosen. Broadcast WAV files (BWF) and RF64 files above four gigabytes are handled the same way as plain WAV.

Choosing a bitrate for a lossless source

Because a WAV has lost nothing yet, the bitrate you pick is the only thing deciding the result. 320 kbps is the format's ceiling and the closest MP3 gets to the original; most people cannot distinguish it from the source in a blind comparison. 192 kbps is where the curve flattens for typical listening, and it is the default here. Below 128 kbps, cymbals and applause start to sound smeared on music, but for a lecture or an interview the same bitrate is generous. Variable bitrate is worth considering for anything long: it spends the bits where the sound is complicated and saves the rest.

What happens to tags

WAV has no mandatory place for artist, album or cover art, and most programs write none. But when a title and an author are there after all — in the LIST INFO chunk of a WAV, or the NAME and AUTH fields of an AIFF — they are carried into the ID3v2.3 tags of the resulting MP3 rather than dropped. When there is nothing to carry, the MP3 comes out with an empty ID3v2.3 block ready to fill, which beats a file with no tag structure at all. Uncompressed PCM never holds cover art, which is why there is no switch for it here; you can add tags afterwards in Edit audio tags.

Frequently asked questions