The parameter of “mg” on a pack of ordinary cigarettes and on a bottle of liquid for e-cigarettes means completely different things. “Mg” on a pack of ordinary cigarettes shows how many substances enter the body. “Mg” on a bottle of e-liquid brands means how much substance is contained in this liquid. And only about one-third of this amount of e-liquid ingredients enters the body, and possibly even less (some studies have shown that the minimum absorption rate of these substances is 10%, the maximum is about 40%). We will accept conditionally this quantity for 30%.
The amount of e-liquid nicotine consumed

A pack of cigarettes “gives out” somewhat 20 mg of nicotine (20 * 1mg). 2 ml of liquid “gives out” approximately 2 * 36 * 0.3 = about the same: 20 mg will enter the body. So, a pack of cigarettes is, roughly speaking, the equivalent of 2 ml of liquid with a strength of 36 mg, or 3 ml of liquid with 24 mg of strength. Cartridges models 510/901 can hold up to 0.5 ml of liquid (maximum); 2 ml = about 4-5 cartridges (note, some cartridges are larger in size).

The amount of consumed e-liquid flavors directly depends on the needs of users, as well as what e-cigarettes they use. Some studies have shown that when vaping cheap premium vape juice nicotine there get about 10 times less nicotine into the blood than when smoking conventional cigarettes.
Vaping e-cigarettes is certainly better for many reasons – not just because they have less nicotine. When smoking conventional cigarettes, it is often necessary, for example, to smoke a cigarette to the end (we all know how harmful it is); we constantly have to run out of the office to smoke, there is not enough time sometimes because of this.