Which audio format should you use?
Nine formats, what each is actually for, and the two rules that settle most decisions.
| Format | Type | Size | Support | Best for |
|---|---|---|---|---|
| MP3 | Lossy | 1 MB/min at 128 kbps | Universal | Anything that has to play everywhere, on anything, including a 2006 car stereo. |
| AAC / M4A | Lossy | 0.9 MB/min at 128 kbps | Very wide | Better than MP3 at the same bitrate. The default for Apple devices and YouTube. |
| Opus | Lossy | 0.5 MB/min at 64 kbps | Modern browsers, Discord, WhatsApp | The best quality per byte by a wide margin, especially for speech. Poor legacy hardware support. |
| OGG Vorbis | Lossy | 1 MB/min at 128 kbps | Wide except Apple | Royalty-free. Standard in game engines like Unity and Godot. |
| WMA | Lossy | 1 MB/min at 128 kbps | Windows-centric, declining | Legacy only. Convert away from it rather than to it. |
| FLAC | Lossless | 5 MB/min | Wide except older Apple | Archiving and distribution where quality must be bit-perfect but size still matters. |
| ALAC | Lossless | 5.5 MB/min | Apple ecosystem | FLAC’s equivalent for people living inside Apple software. |
| WAV | Uncompressed | 10 MB/min at 44.1 kHz stereo | Universal | Editing and mastering. Never for distribution. It is ten times the size for no audible gain. |
| AIFF | Uncompressed | 10 MB/min | Universal | The Mac world’s WAV. Functionally interchangeable. |
The two rules that settle most decisions
Edit in lossless, distribute in lossy. Every time you decode and re-encode a lossy file you lose a little more, the way a photocopy of a photocopy degrades. Keep WAV or FLAC while you are working, and encode to MP3 or AAC exactly once, at the end.
Pick for the worst device that has to play it. Opus is technically the best lossy codec available, but if the file needs to play on a ten-year-old car stereo, its technical superiority is irrelevant. MP3 remains the correct answer more often than audio people like to admit.
What bitrate is actually enough?
For music in MP3, 192 kbps is where most listeners stop being able to pick the compressed file out of a pair in a blind test, and 256 kbps is comfortably transparent for nearly everyone. 320 kbps exists mostly for peace of mind. Below 128 kbps you start hearing it on cymbals and applause first. Dense high-frequency noise is what MP3 handles worst.
For speech, the numbers drop dramatically. A voice recording at 64 kbps mono AAC sounds fine, and Opus at 32 kbps is genuinely usable. A podcast does not need 192 kbps stereo, and shipping one at that rate triples your hosting bill for something nobody can hear.
AAC buys roughly a 20–30% bitrate advantage over MP3 at equivalent quality; Opus roughly doubles it again at low bitrates. So 128 kbps AAC is about the same as 160–192 kbps MP3, and 64 kbps Opus beats both for voice.
Sample rate and bit depth
44.1 kHz is the CD standard and covers everything humans can hear. Sampling theory means it reproduces frequencies up to 22 kHz, which is already above most adults' hearing. 48 kHz is the video and broadcast standard. Higher rates matter during production, where processing artefacts can fold back into the audible range, but they buy nothing in a finished file.
Bit depth controls dynamic range, not fidelity: 16-bit gives 96 dB, more than any listening environment can use, while 24-bit gives 144 dB and exists so engineers can record with generous headroom and normalize later without amplifying noise. Deliver 16-bit; work in 24-bit or float.
The formats to avoid
Do not distribute WAV. It is ten times the size of a transparent MP3 and nobody can hear the difference on a finished master. Do not convertto WMA in 2026 unless a specific device demands it. And do not convert a lossy file to FLAC expecting improvement, you get a lossless copy of the damage that was already done, at five times the size.
Converting between formats is free of extra loss only when the source is lossless. If you have an MP3 and need an M4A, you will lose a small amount; there is no way around that, and it is usually inaudible for a single conversion at a decent bitrate.
Convert between any of these
The audio converter handles every format on this page, in your browser, with nothing uploaded. MP3 and WAV are instant; the rest load a converter once and then stay fast. If your goal is a smaller file rather than a different format, thefile size reducer shows the projected size before you commit.