Way back in the day when vaping was fairly new and much less complicated than it is now, the amount of nicotine in an eliquid was equated to different strengths of cigarettes. For example, 24 mg of nicotine was roughly the equivalent to a pack of Marlboro Reds (shorts). 12 mg was similar to a pack of Marlboro Lights... and so on. Today, we have sub-ohm coils, voltage vs. wattage vs. temperature control, etc. The sub-ohm alone, without adding in how coils and tanks are so much more efficient in nicotine delivery, totally skew the old way of figuring out the nicotine per pack per tankful ratio. Sorry, but I haven't heard anything that helps figure it now these days with today's equipment.