The short answer: WAV inside the studio, MP3 outside it
The WAV vs MP3 debate has a clean answer once you stop asking which format is better and start asking where the file is going. Inside the studio, WAV. Outside it, MP3.
WAV is uncompressed PCM audio: every sample your recorder or DAW captured, nothing removed, roughly 10 MB per minute at CD quality. MP3 is lossy compression: an encoder analyzes the signal, discards the parts it judges least audible, and shrinks the file to a fraction of the size. At 320 kbps the result is near transparent for most listeners. At 128 kbps it is audibly compromised on good playback gear.
Neither format is wrong. The trouble starts when they swap places: WAV files choking a group chat, or an MP3 quietly becoming the only surviving copy of a song.
Why the studio runs on WAV
Editing, mixing, and mastering all involve reprocessing audio, and reprocessing works best on a complete signal. When you comp takes, print stems, or bounce a mix, WAV in and WAV out means no encoder ever touches the audio. You can render, reopen, and re-render as many times as a project demands and the file never degrades.
Sample libraries ship as WAV for the same reason. Producers pitch samples down, stretch them, filter them, and layer them, and heavy processing magnifies whatever is already in the file. You want the file to be complete before you start bending it.
A note on AIFF, since DAWs offer it next to WAV: it is the same uncompressed PCM audio in Apple's container instead of the Windows-origin one, with better native support for tags. Sonically the two are identical, so use whichever your tools prefer.
Why bouncing to MP3 early bites you later
Here is the failure mode we keep seeing. You bounce a beat to MP3 because the WAV felt heavy, the session gets archived or deleted, and a year later the song matters: someone wants to master it, license it, or cut a remix. All you have is the MP3, and everything the encoder threw away is gone for good. Lossy to lossless conversion never restores lost quality. Converting that MP3 to WAV just gives you a much larger file with the same MP3 audio inside, which is worth doing only when a tool insists on WAV input.
Early bouncing also stacks losses. Every lossy to lossy re-encode adds a small generation loss, so an MP3 that gets trimmed and re-exported, then normalized and re-exported again, is paying the encoder's toll at every step. One encode at the end of the process is fine. Five encodes scattered through it are not.
Mastering is where this stings most, because a mastering pass is exactly the kind of critical processing that deserves the full file. The same goes for AI voice conversion, the job we built our desktop app around: whatever does the heavy processing on your audio, hand it a WAV.
What your recorder and your DAW hand you
Most of your tools already default to the right thing. DAWs bounce to WAV or AIFF unless you tell them otherwise, and dedicated recorders write WAV for the same reason. If the big file shows up on your drive, that is the format doing its job: your only decision is when to make the small copy.
Phones are the exception. iPhone voice memos are M4A: lossy AAC in an MP4 container, more efficient than MP3 at the same bitrate and the Apple ecosystem default. That is a sensible format for a phone, but it means your voice memo ideas are already lossy the moment they exist. Get the file off the phone with AirDrop, Files, or email, convert it on the computer if a tool needs WAV, and accept that the take is demo quality. If the melody is worth keeping, re-record it properly through an interface.
When to shrink it, and to what
Once the mix is done and the WAV master is saved, shrink freely. MP3 is the format the whole world can play, and for sharing that universality beats fidelity. Rough mix to the band, demo to a promoter, reference bounce for the car: all better as MP3.
For anything people will actually judge the sound on, encode at 320 kbps. Reserve lower bitrates for cases where size genuinely matters more than sound. We wrote a separate guide on choosing an MP3 bitrate if you want to pick a number with more care.
For the shrinking itself, use our free Audio Converter. Drop the WAV in, pick a bitrate from 128 to 320 kbps, download the MP3. It converts MP3, WAV, M4A, FLAC, OGG, and AIFF using FFmpeg compiled to WebAssembly, so it runs in the browser, nothing uploaded, we never see the file. There is also a dedicated WAV to MP3 converter if that is the only direction you ever travel.
A file policy that never bites
You can compress all of this into four habits. Sessions, stems, and samples stay WAV or AIFF. Masters get archived lossless: plain WAV, or FLAC if storage is tight, since FLAC packs the same audio into 50 to 60 percent of the size and carries proper tags. MP3s are exports, made at the end, treated as copies. And the WAV never gets deleted just because an MP3 of it exists.
Follow those and the WAV vs MP3 question mostly answers itself. The big file is the asset. The small file is the messenger. Keep the asset, send the messenger.