DIY Juice Calculator can do it in the Tools > Simple Calculator options but we need to know how much 60/40 juice you have. According to the calculator if you have 30ml of 60/40 (18ml pg and 12ml of vg) you would need to add 30ml of VG to end up with 60ml total (42ml of vg and 18ml of pg) and running the math in my head that works out.
no problem, I was pretty good at math in high school (a looong time ago) and I too would have probably had trouble trying to do the math in my head. The juice calc makes everything much easier.Thanks fozzy!! that was fast..