WAV is useful for production but can be large. MP3 is often a better delivery format when file size and compatibility matter.
Why is WAV larger?
Working WAV files commonly contain uncompressed PCM samples. MP3 uses lossy compression to store much less data. WAV → MP3 is therefore best viewed as creating a delivery copy, not replacing your best source.
Convert WAV to MP3 locally
Use the audio converter, choose your WAV and select MP3 as output. The conversion runs locally in the browser. The main Audio guide also covers FLAC, OGG, Opus and M4A. For the opposite workflow, see MP3 to WAV.