Question: how do you know how much nicotine is in vape juice?
Answer: If you need to work out the total amount of nicotine in a bottle or in a tank, just multiply the strength in mg/mL by the number of milliliters of it you have. For example, if you fill up a 5 mL vape tank with 6 mg/mL e-liquid, you have 5 mL × 6 mg/mL = 30 mg of nicotine in your tank.