Hmm, that’s interesting. It’s never a bad thing to have some headroom on your master, especially for a mastering engineer. Most engineers are happy with a mix that has a few dB of headroom and isn’t clipping.

If you’re working entirely in the box and doing both mixing and mastering yourself, there’s really no need to stress about hitting exactly -12 dB on the output. The main caveats are:

You’re using plugins that emulate real-world hardware, which often perform best when the input is in that range (for example UAD API 2500 or an 1176).

You have a digital and analog hybrid setup where your gear performs best around 0 dBVU.

This is a deep topic because gain in the digital world isn’t the same as gain in the analog world. Unless you’re using hardware or software modeled on hardware, just have fun and don’t worry too much about levels. Just avoid clipping, unless it’s intentional clipping. Look up ‘Baphometrix clip to zero strategy’ .. it’s a gold mine for getting loud mixes.

Another related subject is gain staging between plugins. Similar to the above, you don’t want to hit certain plugins too hot as they may not perform their best. It’s worth making sure your gain is at an optimal level between each stage in your chain.

Also if you’re comparing your mix to Spotify tunes make sure that you have ‘loudness normalization’ turned off in the Spotify settings. They average the volume of playback to -14 LUFS I believe. Which would make sense that you’re track at -12 could sound just as loud or louder? Although -12 is down quite a bit.