Every audio file you'll ever come across involves one choice between fidelity and file size. WAV, FLAC, and MP3 are merely three different ways of dealing with that trade, and after you know what each of them offers, choosing is no longer guesswork.
The thirty-second version
- WAV provides perfect audio in very large files. For recording and editing.
- FLAC provides perfect audio in merely large files. For archiving music you care about.
- MP3 offers very good audio in small files. For listening, sharing, and any situation where compatibility is a concern.
Now the why, because the why is what prevents mistakes.
WAV: the raw material
A WAV file contains sound with no compression at all: the signal from the microphone, sampled thousands of times each second, recorded as a sequence of numbers. A CD-quality WAV uses about 10 MB per minute, so one hour amounts to roughly 600 MB, and none of that space is wasted, exactly. It's simply all spent.
WAV earns that size in two places. Recording, since you want the original capture to remain unaltered. And editing, since every audio editor opens a WAV instantly, browses through it without decoding, and re-saves it a hundred times without any loss between generations.
What WAV is bad at is living on your devices. Nobody needs a 600 MB album.
FLAC: the archivist's format
FLAC is the clever one: lossless compression. It reduces the size of audio the way a ZIP reduces a document, by detecting redundancy and encoding it more efficiently, and when the audio plays back, the output is identical to the original on a bit-for-bit basis. Generally a FLAC lands at about half the size of the corresponding WAV.
That makes FLAC the appropriate place to store music and recordings you truly value: your CD rips, your band's masters, the interview you'll still want in ten years. Half the space of WAV, with none of MP3's loss.
The main drawback is reach. Many dedicated audio players support FLAC now, but a large number of car stereos, older devices, and apps still can't handle it, and nobody emails a FLAC.
MP3: the diplomat
MP3 is lossy: it permanently gets rid of the parts of the sound your ear is least likely to notice, and the result is files only a tenth the size of WAV. When the bitrate is low, a careful listener can detect the difference. At 192 kbps and above, which is where our converters encode, speech is transparent and music is close enough that most people cannot tell it apart from the original on normal equipment.
The true strength of MP3 isn't the compression anymore. It's the thirty years of widespread support. Every device, app, car, and grandparent's computer on Earth plays MP3. Since the nineties, MP3 has been the answer when the aim is for something to play everywhere without any questions being asked.
The one rule that protects your audio
Lossy is a one-way door. Converting MP3 to WAV or MP3 to FLAC produces a large file containing exactly the same missing information as the MP3 it came from. The format gets fancier; the sound does not improve. Nothing recovers what lossy compression discarded.
Therefore the rule: retain a lossless master of anything you value, and create lossy copies for everyday use. The practical patterns:
- Recorded something important? Keep the WAV, make an MP3 for sharing.
- Hard drive being eaten by a WAV library? WAV to FLAC halves it with no loss.
- FLAC collection won't play in the car? FLAC to MP3 for the road copies, keep the FLACs at home.
- Older AIFF files from a Mac? AIFF to MP3 or AIFF to FLAC, same logic, Apple flavor.
The only truly incorrect moves are the two involving destruction or pretending: deleting your lossless originals to save space you could have saved with FLAC, and converting an MP3 into a lossless container with the expectation that it will sound better.
Converting between them
On FormatFusion all of these conversions run free within your browser, powered by FFmpeg compiled to WebAssembly. Your audio is never sent to any server, there is no daily usage limit, and files up to 1 GB each convert free, which covers hours of audio in any of these formats. FormatFusion Pro adds exact bitrate control (128 to 320 kbps) when you want to set the MP3 trade yourself.
Begin with the pair in front of you: WAV to MP3, FLAC to MP3, or the full audio list. Your ears, your call, your hardware doing the work.