User blog comment:Slashingstrike/Vampirizer/@comment-15077371-20160827161416/@comment-15077371-20160828133504

So here's what i come up with

25g - On hit effect 25g 37.5g - lifesteal (25 + 37.5) / 2 = 31.25 or ~ 31.5

31.5 x 15 = 472.5 health steal because it does damage on hit and heals