Peak meter is the best way to check your peaks in the mix

what i recommend is before you export your mix
play it and see what the peak meter reads

if its too high then lower your mix buss fader and run the song again and see where the peak meter reads.

its good to have headroom
some mixes come to me with headroom of -6 db some in - 3 db and some in others

most peak meters in the softwares are good enough for the job