There are two primary types of normalization:
) is a widely recognized target level for "quiet" or standard listening on certain platforms and mobile devices. Spotify Android Target
By using Sound Normalizer 87 Verified, you can:
Broadcast/compliance
Audio Normalization: What Is It and Should I Care? - Home Brew Audio
If you are a musician, normalizing to 87% leaves approximately 2 dB of headroom. This allows a mastering engineer to apply EQ, compression, or limiting without immediately clipping the mix.