MP3 vs WAV vs FLAC: Which Audio Format Should You Use?

Lossless vs lossy: the one distinction that matters

Every digital audio format stores the same thing, a long list of numbers describing the sound wave, but they store it in different ways.

• Lossless formats keep every number exactly. Decode a FLAC and you get back precisely the samples that went in. WAV doesn't compress at all, while FLAC and ALAC compress the data much as a ZIP file does, with nothing thrown away.
• Lossy formats use a psychoacoustic model to discard sounds that human hearing is unlikely to notice, such as quiet frequencies masked by louder ones. This makes files 5–15 times smaller, but the discarded information is gone for good.

At sensible settings, a well-encoded lossy file is very hard to tell apart from the original in normal listening. The difference shows up when you process audio: editing, separating stems, pitch-shifting or re-encoding all expose the missing detail.

The formats at a glance

WAV: the working format

WAV (Waveform Audio File Format) was introduced by Microsoft and IBM in 1991 and simply stores raw PCM samples. Because there's nothing to decode, every audio editor, video editor, sampler and DJ system can read it instantly, and saving it repeatedly never degrades the sound. The downside is size: a 3-minute song is about 30 MB.

Use WAV when you're editing, mixing, separating stems or handing files to another producer. Convert MP3s with the MP3 to WAV tool before heavy editing so you don't stack compression losses.

FLAC: lossless, but half the size

The Free Lossless Audio Codec (first released in 2001) shrinks audio to roughly half to two-thirds of its WAV size with zero quality loss, and it supports tags and cover art. It's the standard for archiving CD rips and for downloads from hi-res music stores.

Use FLAC when you want to keep a perfect copy of your music collection without filling your drive. Some older devices and car stereos can't play it, so keep MP3 copies for those.

MP3: still the universal choice

MP3 (MPEG-1 Audio Layer III) dates from the early 1990s and its patents have expired, so it's supported by practically every device and website ever made. At 192–320 kbps, most listeners can't distinguish it from the original in blind tests.

Use MP3 when a file simply has to play everywhere: car stereos, old phones, smart TVs, website upload forms, podcast hosts. Our MP3 Converter turns almost any audio or video file into MP3.

AAC / M4A: MP3's more efficient successor

AAC achieves similar quality to MP3 at somewhat lower bitrates and is the default for iPhone recordings, Apple Music and the soundtracks of most MP4 videos. The .m4a extension is simply AAC audio in an MP4 container. It's widely supported, but a few older devices and web forms only accept MP3.

OGG Vorbis and Opus: the open alternatives

Ogg Vorbis is a royalty-free lossy codec popular in games. Opus (standardised in 2012) is remarkably efficient at low bitrates and powers voice calls and voice messages in many chat apps. Both decode in modern browsers, so you can convert them to MP3 if another app won't open them.

Which format should you choose?

• Recording or editing: WAV, 24-bit if your interface supports it.
• Archiving a music collection: FLAC (or ALAC for Apple users).
• Sharing a song or podcast: MP3 at 128–192 kbps, or AAC.
• Emailing a long voice recording: MP3, mono, 64 kbps. See our guide to reducing audio file size.
• Sending to a DJ, sampler or CD burner: 16-bit, 44.1 kHz WAV.

Common mistakes to avoid

• "Upgrading" an MP3 to WAV or FLAC to improve quality. It sounds identical, just larger.
• Re-encoding MP3 to MP3 repeatedly. Each pass loses a little more detail ("generation loss").
• Encoding at a higher bitrate than the source. A 128 kbps MP3 converted at 320 kbps is still a 128 kbps-quality file.

Frequently asked questions