Lossless vs Lossy Audio: When Does the Difference Matter?

Last updated: 28 October 2026

When you save audio as MP3 or FLAC, you are choosing between two kinds of compression. Understanding the difference saves space and keeps you from mistakes that cannot be undone, such as deleting the original after converting.

Lossless compression

It shrinks the file without removing any information, and when decoded you get audio identical to the source, much like putting a file in a ZIP. Examples include FLAC and ALAC. A typical WAV file is usually not compressed at all.

Lossy compression

It removes information that is assumed to be inaudible, in order to shrink the file a lot. This relies on the science of hearing: the ear does not pick up quiet sounds that occur alongside louder ones close in time or frequency, so the encoder drops them. Examples include MP3, AAC (in M4A), Vorbis and Opus. The lower the bitrate, the more is removed.

Size comparison

One minute of CD-quality audio (stereo, 44.1 kHz, 16-bit):

Format	Type	Approximate size
WAV	Uncompressed	10.6 MB
FLAC	Lossless	Often between half and two thirds of that
MP3 (320 kbps)	Lossy	2.4 MB
MP3 (128 kbps)	Lossy	0.96 MB

When does the difference matter?

Recording and editing: always work from a lossless copy (WAV or FLAC). Every save in a lossy format removes more.
Archiving: keep the lossless original, because what was removed cannot be recovered.
Distribution and everyday listening: MP3 or M4A at a suitable bitrate saves space and plays on every device.
Transcription: see best audio settings for transcription.

Common mistakes

"Converting MP3 to FLAC improves quality." Not true. Removed detail does not come back, and the file just gets bigger.
Repeatedly converting between lossy formats. Each pass removes more. Convert once from the original.
Assuming "lossless" is always better for listening. At high bitrates many people cannot tell the difference. Try it yourself: convert a track you know to 128, 192 and 320, and listen without knowing which is which.

What should you do in practice?

Keep an original lossless copy.
From it, make MP3 or M4A copies for your phone and for sharing, once, at the bitrate you need.
Use the Sayvoi converter for the conversion; you can convert a whole collection at once.

Further reading: which audio format should you choose?, convert FLAC to MP3 and CBR vs VBR.

Frequently asked questions

Is FLAC better than MP3?

FLAC is more exact because it removes nothing, but it is bigger and does not play on every device. Which is better depends on your use.

Is WAV lossless compression?

Usually not. A typical WAV file is uncompressed (PCM); FLAC is what compresses it without loss.