MP3, M4A, WAV, FLAC and OGG compared

Lossy vs lossless: the one difference that matters

Lossless formats keep every detail of the recording. WAV stores the raw samples as they are; FLAC packs the same samples more tightly, like a ZIP file for sound, and unpacks them exactly. Play a FLAC and a WAV of the same recording and you hear the same thing.

Lossy formats — MP3, M4A (AAC) and OGG (Vorbis or Opus) — save space by removing sound people are unlikely to notice. At sensible bitrates most listeners can't tell the difference on everyday headphones, and the files are a fraction of the size. But the removed detail is gone for good.

Tip: Converting never adds quality back. Turning an MP3 into a WAV makes it far bigger but sounds exactly like the MP3, and converting one lossy format to another (MP3 to M4A, OGG to MP3) loses a little more each time. Convert from the best copy you have, and only once if you can.

How big is a minute of audio?

File size is just bitrate × time. Bitrate is measured in kilobits per second (kbps), and there are 8 bits in a byte, so the maths is easy to do yourself:

• CD-quality WAV: 44,100 samples a second × 16 bits × 2 channels = 1,411 kbps. A minute is 1,411,000 × 60 ÷ 8 ≈ 10.6 million bytes — about 10 MB a minute, or 600 MB an hour.
• 128 kbps MP3: 128,000 × 60 ÷ 8 = 960,000 bytes — about 1 MB a minute.
• 192 kbps: about 1.4 MB a minute. 320 kbps: about 2.4 MB a minute. 96 kbps: about 0.7 MB a minute.
• FLAC: varies with the recording, because it compresses without loss — often somewhere around half to two-thirds of the WAV size.

The bitrate maths is the same for MP3, M4A and OGG, so at the same bitrate they come out roughly the same size. What differs is how good they sound at that size: AAC and Opus are newer designs and generally sound better than MP3 at the same bitrate, especially at lower bitrates.

The formats side by side

Which one should you choose?

To send or play anywhere: MP3

MP3 is the safe answer when you don't know what the other person uses. 192 kbps is a good default for music; 128 kbps is plenty for speech and keeps files small; 320 kbps is the highest MP3 bitrate.

For Apple devices and music libraries: M4A

M4A holds AAC audio — what iPhone voice memos and many music stores use. It sounds a little better than MP3 at the same size and is also the basis of iPhone ringtones (see how to make a ringtone).

For editing: WAV

Audio editors, samplers and some upload forms want WAV. Because nothing is compressed, editing and re-saving doesn't add loss — but the files are around ten times bigger than a 128 kbps MP3.

For keeping a master copy: FLAC

FLAC is the usual choice for ripping CDs or keeping originals: full quality at a smaller size than WAV. When a phone, car or app won't play it, make an MP3 copy for that device and keep the FLAC.

For the web and games: OGG

OGG with Opus is efficient and widely used in browsers and games, but it's the least likely to play in older or simpler players. If someone says your file won't open, OGG is the usual suspect.

Converting between formats

The Audio Converter reads MP3, WAV, OGG, FLAC and M4A — plus the sound from MP4 and WebM files — and saves as MP3, M4A (AAC), WAV or OGG (Opus). For the lossy outputs you choose 96, 128, 192 or 320 kbps. It doesn't write FLAC, so keep your FLAC originals and convert copies.

There are ready-made pages for the most common jobs: WAV to MP3, M4A to MP3, FLAC to MP3, OGG to MP3 and MP3 to WAV. The conversion runs in your browser, so the files stay on your device. It relies on the browser's built-in media support (WebCodecs): recent Chrome, Edge and Safari 17+ work best, and Firefox handles most files.

If the sound you want is inside a video — a lecture, a concert clip, a screen recording with narration — Video to MP3 saves just the soundtrack as MP3, M4A, WAV or OGG, with the same bitrate choices.