Does converting MP3 to FLAC improve quality?
No. FLAC is lossless, which means it stores exactly what you give it — and what you are giving it is audio an MP3 encoder already stripped detail out of. The conversion preserves the degraded version perfectly in a much larger file. Nothing is recovered.
The only thing a lossless container buys you at that point is protection against further loss: re-encoding MP3 to MP3, or MP3 to AAC, discards more each time. So if a lossy file is all you have and it must be edited or re-rendered, working in a lossless format from then on stops the decline — it just cannot reverse it.
Audio File Format Guide
Compare audio formats side-by-side. Find the right format for streaming, archiving, editing, or sharing.
Format Comparison Table
| Format | Type | Quality | Size (1 min stereo) | Best For |
|---|---|---|---|---|
| WAV | Uncompressed | Lossless | ~10 MB | Editing, mastering |
| FLAC | Compressed | Lossless | ~5 MB | Archiving, audiophile |
| ALAC | Compressed | Lossless | ~5 MB | Apple ecosystem |
| MP3 | Compressed | Lossy | ~1.5 MB @128k | Sharing, compatibility |
| AAC | Compressed | Lossy | ~1.2 MB @128k | Streaming, mobile |
| OGG | Compressed | Lossy | ~1.3 MB @128k | Web, games, open source |
| OPUS | Compressed | Lossy | ~0.8 MB @96k | VoIP, streaming, low bitrate |
| AIFF | Uncompressed | Lossless | ~10 MB | Mac editing |
| WMA | Compressed | Lossy | ~1.5 MB @128k | Windows legacy |
Format Finder
FFmpeg Quick Commands
Common conversion commands using FFmpeg:
Lossy vs Lossless
Lossless formats (WAV, FLAC, ALAC) preserve every sample of the original recording. Lossy formats (MP3, AAC, OGG) remove inaudible data to achieve smaller files. Converting lossy to lossless does NOT restore lost data. Always keep a lossless master copy and generate lossy versions from it.
Complete guide to audio file formats. Compare MP3, WAV, FLAC, AAC, OGG, ALAC quality, file sizes, and find the best format for your needs.
Related tools
Frequently asked questions
What does lossy actually cost me?
Size against fidelity, and the size gap is large. On this page's table a minute of stereo runs about 10 MB as WAV, about 5 MB as FLAC, and about 1.5 MB as MP3 at 128 kbps. Lossless formats keep every sample; lossy ones discard what the encoder judges you will not hear, and that discard is permanent.
Which format should I archive in?
FLAC or ALAC. Both are compressed but lossless, so they are roughly half the size of WAV with nothing thrown away — the table lists both at about 5 MB a minute against WAV's 10. ALAC is the one that fits the Apple ecosystem; FLAC is the more widely supported of the two.
Why is Opus so much smaller?
Because it is a newer codec designed for low bitrates, and the table rates it at about 0.8 MB a minute at 96 kbps against AAC's 1.2 MB at 128. It is listed for VoIP, streaming and low-bitrate work. The trade is support: MP3 plays everywhere, Opus does not.
Does converting between lossy formats lose more quality?
Yes. Each lossy encode throws away data, and a second one throws away more from an already reduced signal — going MP3 to AAC is worse than going to either from the original. Keep a lossless master and export from that; the FFmpeg commands on this page all start from one for that reason.
Lossless, lossy, and the one conversion to avoid
Audio formats split into two families. Lossless formats (FLAC, ALAC, WAV, AIFF) keep every sample; FLAC and ALAC compress the file without discarding anything, WAV and AIFF do not compress at all. Lossy formats (MP3, AAC, Opus, Vorbis) throw away detail the encoder judges inaudible, which is how they get small.
The rule that follows is simple: converting lossless → lossless loses nothing, and lossless → lossy loses a fixed amount once. Lossy → lossy is the one to avoid, because the second encoder cannot recover what the first discarded and throws away more on top. This is generation loss, and it accumulates with every pass. Converting an MP3 to FLAC does not undo it either — it stores the already-degraded audio in a bigger file.
| Format | Family | Typical use |
|---|---|---|
| WAV / AIFF | lossless, uncompressed | editing, mastering |
| FLAC / ALAC | lossless, compressed | archiving, library playback |
| AAC | lossy | streaming, Apple ecosystem |
| MP3 | lossy | widest compatibility |
| Opus | lossy | voice and low-bitrate streaming |
Sample rate and bit depth
Sample rate is how often the waveform is measured, in kilohertz; bit depth is how finely each measurement is recorded. CD audio is 44.1 kHz / 16-bit, and most recording is done at 48 kHz to match video. Higher figures give an editor headroom for processing, which is where they earn their size — the audible benefit on a finished file is a long-running argument and not a settled fact.
Resampling is not free. Converting 48 kHz to 44.1 kHz is not an integer ratio, so it is interpolation, and a poor resampler leaves artefacts. Where you can, record and deliver at the same rate and resample once, at the end, rather than twice.
Bitrate, constant and variable
For lossy formats bitrate is the budget per second. A constant bitrate spends the same on silence as on a dense passage; a variable bitrate moves the budget to where it is needed and usually sounds better at the same file size. Variable is the sensible default unless something downstream demands constant.