Convert MP3 to WAV

How to use it#

1. Drop an MP3 onto the box above, or click it to choose one.
2. To keep only part of it, set the start and end, typed or taken from the player with Set from player.
3. Play the WAV in the preview, then download it.

When you need a WAV#

A WAV holds sound uncompressed, so any program can read it without a decoder, and nothing is lost when it is edited and saved again. That is why audio editors, video editors, samplers, some DJ and karaoke software, programs that burn audio CDs, and plenty of upload forms for radio, podcasts, or phone systems ask for WAV rather than MP3.

The WAV made here is the most common kind: 16-bit PCM at the MP3's own sample rate, usually 44.1 kHz, and the same channels, stereo or mono. Every program that opens WAV opens this one.

What it does to the sound, and the size#

Nothing is lost in this direction. The MP3 is decoded once and written out sample by sample, so the WAV sounds exactly like the MP3. It does not sound better, either: what the MP3 left out when it was made is gone, and no conversion can bring it back. A WAV made from an MP3 is still an MP3 underneath, which matters if a site asks for lossless or "studio quality" audio.

The file grows a lot. A WAV at 44.1 kHz stereo takes about 10 MB a minute, against 1.4 MB for a 192 kbps MP3, so a four-minute song goes from about 6 MB to 40 MB. A browser makes files of up to 2 GB, which is about three hours of CD-quality stereo; for longer recordings, convert them in parts with the start and end.

Why the WAV is a little longer#

An MP3 encoder adds a short silence at the start of the file, and pads the end out to a whole frame, together usually about a twentieth of a second. Many players skip it, using a note the encoder leaves in the file. The WAV keeps it, so a song is a few hundredths of a second longer in the WAV than the player showed. It matters only when lining sounds up to the millisecond in an editor, where the silence at the start is easy to trim.