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The blood alcohol content is usually calculated using ppm. 0.5 per mille of alcohol means that there are 0.5 grams of alcohol per liter of body fluid. This section gives examples of how to calculate the approximate blood alcohol content.

Example 1. A man weighing 80 kg drinks 1 bottle of beer (330 ml) containing 5% alcohol. How many milliliters of alcohol are in his blood? To determine this, it is necessary to consider the fact that body fluids make up about 70% of the total body weight; in this case 56 kg. The beer drunk contains 13 grams of pure alcohol. Per 1 kg of body fluid there is, therefore:

13g/56kg = approx. 0.23 g

This means that per 1000 g of body fluid there are 0.23 g of pure alcohol or 0.23 per millilitre.

Example 2. A woman weighing 55 kg drinks 1 bottle of beer (330 ml) containing 5% alcohol. The calculation now looks slightly different. The fact is that, firstly, the woman's body mass is smaller and, secondly, the liquid in the woman's body is only about 60% of the total weight. In this case, it is 33 kg. So for every 1 kg of body fluid:

13g/33kg=0.39 g or 0.39 per millilitre.

So, for the same amount of alcohol drunk, a woman will have more alcohol in her blood than a man. Unfortunately, the number of milliliters can only be roughly calculated using this method. In reality, blood alcohol content is determined by a whole range of factors: body weight, gender, age, type and quantity of drink consumed, rate of alcohol absorption, drinking pattern…