MP3 vs WAV vs FLAC: which audio format should you use?

MP3, WAV and FLAC are the three audio formats you are most likely to meet, and they represent three completely different ideas about sound: throw some of it away to save space, keep all of it raw, or keep all of it but pack it efficiently. Once you understand that difference, choosing between them becomes easy.

The short answer

• MP3 is lossy: it discards parts of the signal that listeners are unlikely to notice, so files are small. Ideal for everyday listening and sharing.
• WAV is uncompressed: it stores the raw audio samples exactly as recorded. Ideal for editing, recording and production.
• FLAC is lossless: it compresses the audio like a ZIP file does, so it is smaller than WAV but decodes back to the exact same samples. Ideal for archiving and high-quality music libraries.

MP3: small files, some quality traded away

MP3 uses a psychoacoustic model: it analyses the sound and removes detail that human hearing tends to mask, such as quiet sounds right next to loud ones. How much is removed depends on the bitrate:

• 128 kbps: compact, fine for speech, podcasts and casual listening.
• 192 kbps: a sensible middle ground for music; most people find it hard to tell apart from the original on typical headphones.
• 320 kbps: the highest standard MP3 bitrate, for when you want the best MP3 can offer.

The catch is that the discarded information is gone for good. MP3 also plays literally everywhere: phones, cars, browsers, old MP3 players, smart speakers.

WAV: raw and simple

A WAV file is essentially a header followed by the raw PCM samples. Nothing is compressed and nothing is lost, which makes WAV quick to read and easy for any audio editor to work with. That simplicity has a cost: size. At CD quality (44.1 kHz, 16-bit, stereo) the math is 44,100 samples × 2 bytes × 2 channels ≈ 176 KB per second, or roughly 10 MB per minute. A four-minute song is around 40 MB.

WAV also has weaker metadata support than MP3 or FLAC, so titles, artists and cover art often get lost, and the classic format has a 4 GB file size limit.

FLAC: lossless, but smaller

FLAC (Free Lossless Audio Codec) takes the same samples a WAV holds and compresses them without discarding anything. Decode a FLAC and you get back a bit-identical copy of the original audio. How much smaller the file gets depends on the material: dense, loud music compresses less than quiet or simple recordings, but FLAC files are usually substantially smaller than the equivalent WAV. FLAC also supports rich tags and embedded cover art, and it is an open, royalty-free format.

How big do the files get?

Approximate sizes for stereo audio at 44.1 kHz:

Format	Per minute	4-minute song
WAV (16-bit)	≈ 10 MB	≈ 40 MB
FLAC	varies, smaller than WAV	varies
MP3 320 kbps	≈ 2.4 MB	≈ 9.6 MB
MP3 192 kbps	≈ 1.4 MB	≈ 5.8 MB
MP3 128 kbps	≈ 1 MB	≈ 3.8 MB

MP3 sizes follow directly from the bitrate: 192 kbps means 192,000 bits, or 24 KB, every second.

When to use each

• Listening on the go, sharing, uploading to a website: MP3. Small, universal, good enough for most ears at 192 kbps or above.
• Recording, editing, mixing, or sending audio to a video editor: WAV. No decoding overhead, no generation loss while you work, accepted by every DAW.
• Archiving a music collection or keeping masters: FLAC. Full quality at a fraction of the WAV size, with proper tags.
• Voice memos, audiobooks, podcasts: MP3 at 128 kbps is usually plenty.

Conversion is a one-way street for quality

This is the most important rule: converting an MP3 to WAV or FLAC does not bring back lost quality. The result is a bigger file containing exactly the same MP3-level sound. It can still be useful, for example when an editor only accepts WAV, but it is not an upgrade.

The sensible order is always from better to smaller: keep a WAV or FLAC master, and produce MP3s from it when you need them. Also avoid re-encoding MP3 to MP3 repeatedly; each lossy pass can add artifacts.

Converting on Azpy

• To MP3 (from WAV, FLAC, M4A, OGG, AAC or Opus) runs entirely in your browser, using the LAME encoder compiled for the web. You pick 128, 192 or 320 kbps; 192 kbps is the default. Your file is never uploaded.
• To WAV also runs in your browser, with no upload.
• To FLAC (for example WAV to FLAC) runs on our server with FFmpeg, and the file is deleted automatically right after conversion.

Browser tools accept files up to 25 MB for free. Because WAV is so large, a WAV of just a few minutes can already hit that limit, which is one more reason to keep long recordings in FLAC. You can browse every converter on the tools page.

A rule of thumb

Listening → MP3. Working → WAV. Keeping → FLAC. And always convert from the highest-quality version you have, never the other way around.