Compress WAV files

WAV is raw sound in a simple wrapper

WAV (Waveform Audio File Format) was defined by Microsoft and IBM in 1991. Like AVI, it is a RIFF file: a short header that states the sample rate, bit depth and number of channels, followed by the samples themselves. Almost every WAV file holds uncompressed PCM audio, which is why recording apps, audio interfaces, DAWs, field recorders and sound-effect libraries use it: there is nothing to decode, and nothing is lost.

Uncompressed audio has a fixed size per second that you can calculate:

A three-minute song on a CD is therefore about 32 MB as WAV, too big for an email attachment in most services.

Lossless or lossy: two ways to shrink a WAV

Lossless. FLAC predicts each sample from the previous ones and stores only the small error, so you get back exactly the same samples when you decode it. For music the file typically becomes 40–60 % smaller; quiet recordings and speech with pauses shrink more, dense and noisy material less. Use this when the file will be edited, mastered or archived. Pick FLAC in the output format menu, because this page defaults to MP3, and set Bit depth to Keep original for 24-bit recordings, because the default is 16-bit.

Lossy. AAC, Opus or MP3 throw away sound you are unlikely to hear. A 128 kbps file is about 11 times smaller than the CD-quality WAV, and for speech you can go much further. Use this when the file only needs to be listened to. In our tests, a generated three-minute CD-quality test WAV of 31.8 MB came out at 2.9 MB as a 128 kbps MP3 and at 13.1 MB as FLAC.

Recommended settings

• Sending a song or demo for listening: AAC or MP3 at 192 kbps, stereo, sample rate unchanged.
• Interview, lecture or voice memo: mono, 64 kbps, 22.05 or 24 kHz. A one-hour interview drops from more than 600 MB of CD-quality WAV to under 30 MB.
• Handing a mix to a mastering engineer or collaborator: FLAC with sample rate and Bit depth set to Keep original, so they receive every sample.
• Sound effects for a website or game: Opus or AAC at 96–128 kbps; turn on "Trim silence at start and end".

Reducing the bit depth from 24 to 16 bits or the sample rate from 96 to 48 kHz also shrinks a file substantially, and for listening on normal equipment the difference is not audible. For production work, keep the high-resolution original.

Things to know

• The 4 GB limit. WAV stores sizes as 32-bit numbers, so a file cannot exceed 4 GB, which is about 6.8 hours of CD-quality stereo. Longer recorders switch to RF64 or split files.
• Markers and loop points. Broadcast WAV (BWF) files carry timestamps and cue points used by editing software. A converted file will not keep them.
• Compressed WAVs. A few WAV files contain ADPCM or other codecs instead of PCM. They are already smaller and may not be readable everywhere.

WAV questions

Other audio tools

Every audio format is listed on the audio compressor page. For lossy output that plays everywhere, see MP3; for how files are handled locally, see how it works.