How to convert audio without losing quality
Which conversions are genuinely lossless, which always cost something, and the one rule that prevents most avoidable damage.
In short
Lossless to lossless is free. Lossless to lossy costs once and is unavoidable. Lossy to anything cannot recover what was already discarded — so always convert from the best source you still have, exactly once.
"Without losing quality" is possible in some directions and impossible in others. Knowing which is which prevents most of the damage people do to their own files.
| From → To | Cost |
|---|---|
| WAV → FLAC | None. Identical audio, smaller file. |
| FLAC → WAV | None. Identical audio, larger file. |
| WAV or FLAC → MP3/AAC/OGG | One round of loss. Unavoidable, and fine at a sensible bitrate. |
| MP3 → WAV or FLAC | No further loss, but no recovery either. Just a much bigger file. |
| MP3 → MP3, or MP3 → AAC | A second round of loss on top of the first. Avoid. |
The rule
Always convert from the best source you still have, and do it once. If you have the WAV, go WAV → MP3. Do not go WAV → MP3 → AAC because you changed your mind — go back to the WAV.
If lossy is your only source
Sometimes you only have the MP3. In that case: convert once, to the format you actually need, at a bitrate at least as high as the source. Going from 128 kbps to 320 kbps will not improve it, but going to 64 kbps will visibly make it worse.
Sample rate
Convert Audio can also change the sample rate. Reducing it — 44.1 kHz down to 22.05 kHz — halves the data and removes the top octave of frequencies, which is acceptable for speech and destructive for music. Raising it does nothing useful; the missing frequencies were never recorded.
Mistakes worth avoiding
- Converting MP3 to WAV before editing and thinking you have restored quality. You have not; you have only stopped losing more.
- Raising the bitrate on conversion and assuming it improved.
- Trying several formats by converting the previous output each time instead of returning to the original.
Tools used in this guide
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