WAV vs MP3: File Size, Quality and Which to Use

The main difference between WAV and MP3

WAV is a container, usually holding uncompressed PCM audio: a direct list of sample values, exactly as recorded. Nothing is thrown away, so the file is large. MP3 is a lossy compressed format. The encoder uses a model of human hearing to discard sounds that are masked by louder ones or are hard to perceive, then stores what remains efficiently.

WAV and MP3 side by side
	WAV	MP3
Compression	None (usually PCM)	Lossy
Quality	Identical to the source	Depends on bitrate and encoder
Size per minute, stereo	≈ 10.6 MB at CD quality	≈ 1–2.4 MB at 128–320 kbps
Editing	No loss when re-saved	Loses a little each re-encode
Tags and artwork	Possible, but unevenly supported	ID3 tags supported almost everywhere
Maximum file size	4 GB (about 6 h 45 min at CD quality)	No practical limit
Playback support	Almost universal	Almost universal

WAV vs MP3 file size, measured

We generated one minute of stereo test audio at 44.1 kHz, saved it as a 16-bit WAV with the same code the SuperUtils audio tools use, and encoded it with the LAME MP3 encoder at three constant bitrates.

One minute of 44.1 kHz stereo audio
Format	Bitrate (kbps)	Measured size	Compared with WAV
WAV, 16-bit / 44.1 kHz stereo (CD quality)	1,411	10.58 MB (10,584,044 bytes)	—
MP3, 320 kbps	320	2.40 MB (2,401,175 bytes)	4.4× smaller
MP3, 192 kbps	192	1.44 MB (1,440,705 bytes)	7.3× smaller
MP3, 128 kbps	128	0.96 MB (960,470 bytes)	11.0× smaller

These numbers follow directly from the bitrate, so they hold for any audio of the same length. CD-quality WAV runs at 44,100 samples × 16 bits × 2 channels = 1,411,200 bits per second, or 176,400 bytes per second. An hour is therefore about 635 MB as WAV, 86 MB as a 192 kbps MP3, and 58 MB at 128 kbps. Higher-resolution WAV files, such as 24-bit / 48 kHz, are larger still: about 17.3 MB per minute.

Measurement: synthetic 60-second stereo signal (chord plus noise), WAV written by SuperUtils’ 16-bit PCM encoder including its 44-byte header; MP3 encoded at constant bitrate with LAME via the lamejs library. Variable-bitrate MP3s vary with the content.

Can you hear the difference?

Often not, at high bitrates. With a good encoder, a 256 or 320 kbps MP3 is very hard for most people to distinguish from the original in a blind comparison on ordinary headphones or speakers. Differences are more likely to show up at 128 kbps and below, especially on cymbals, applause, reverb tails and other complex high-frequency sound, which can take on a swishy or smeared character.

The bigger risk is repeated encoding. Every time an MP3 is decoded, edited and saved as MP3 again, the encoder discards a little more, and artifacts build up. That is why audio professionals work in WAV and export MP3 only once, at the end.

WAV or MP3: which format for which job

Recommended format by task
Task	Use	Why
Recording music or voice	WAV	Captures everything; edit without loss
Editing, mixing, mastering	WAV	No generation loss while you work
Archiving originals	WAV (or FLAC)	A perfect master you can re-encode later
Sending to a studio or for mastering	WAV	Engineers expect lossless files
Publishing a podcast	MP3	Small downloads; every podcast app plays it
Email, chat or upload limits	MP3	4–11× smaller than WAV
Phone or car music library	MP3 at 192–320 kbps	Good quality, far more songs per GB
Sound effects in a game or video edit	WAV	No encoder delay; clean, exact timing

If you need lossless quality but WAV files are too big, FLAC compresses audio to roughly half its WAV size with no loss at all. It is widely supported, though not by every device and browser.

Converting between WAV and MP3

WAV to MP3 shrinks the file and is the normal last step before sharing. Choose 192 kbps for a good balance or 320 kbps when quality matters most. MP3 to WAV only changes the container: the result is larger but no better, because the discarded detail cannot be restored.

SuperUtils’ audio tools run in your browser without uploading your recordings. The Audio Merger joins clips and saves the result as 192 kbps MP3 or uncompressed WAV. The Audio Trimmer and Silence Remover save WAV files, so you can cut a recording without adding another round of MP3 encoding. Not sure whether a file will play? The Audio Compatibility Checker reports its format, sample rate and channels.

Frequently asked questions

Is WAV better quality than MP3?

A WAV file normally stores uncompressed audio, so it is an exact copy of the recording. MP3 is lossy: it permanently removes detail that is hard to hear to save space. At 256–320 kbps, most listeners find a well-encoded MP3 very hard to tell apart from the WAV, but the WAV is still the better master copy.

How much bigger is a WAV file than an MP3?

For CD-quality stereo audio, a WAV file is about 10.6 MB per minute. In our measurement the same minute was 2.4 MB as a 320 kbps MP3, 1.44 MB at 192 kbps and 0.96 MB at 128 kbps, so the WAV was 4.4 to 11 times larger.

Does converting MP3 to WAV improve quality?

No. Converting an MP3 to WAV makes a much larger file that contains exactly the MP3’s quality. The detail removed during MP3 encoding cannot be recovered. It can still be useful when software only accepts WAV.

Should I edit audio as WAV or MP3?

Edit in WAV or another lossless format, then export an MP3 at the end if you need a small file. Each time an MP3 is decoded, edited and encoded again, a little more quality is lost.

Which format should I use for a podcast?

Record and edit in WAV, then publish MP3. Podcast apps and hosts expect MP3, and speech sounds clear at bitrates such as 96–128 kbps mono or 128–192 kbps stereo.

Is there a maximum size for WAV files?

Yes. The standard WAV format uses 32-bit size fields, so files are limited to 4 GB. That is about 6 hours 45 minutes of CD-quality stereo audio. Formats such as RF64 and W64 remove the limit for long recordings.

WAV vs MP3: which should you use?

10.58 MB vs 2.40 MB