The actual weight of cologne, per fluid oz. (± good-natured imprecision)
Updated: Jun 19, 2021
A thought just blew my mind: Shouldn't cologne/EDT/EDP have a consistent weight per fluid oz.? If it is made mostly of perfumers alcohol, then 3.4 fl oz or 100 ml should weigh pretty much the same. By subtracting that weight from the weight of a bottle, we should know how much an empty bottle weighs. Right?
Now, it appears that perfumer's alcohol, or denatured alcohol, is 99.88% (by wt.) ethanol. And 0.12% t-butyl alcohol (the main "denaturant"), with a itty-bitty bit of Bitrex (denatonium benzoate), perhaps 0.0006% by weight, so we won't count that.
CoolConversion.com says that "1 US fluid ounce of ethanol weighs 23.2 grams. 23.156074 grams precisely."
So 3.4 fluid oz. of 100% ethanol is 78.73 grams, or 2.777 oz. by weight.
Now if we wanted to allow a little good-natured imprecision, we could assume that if you subtracted 78.7 from the weight of a bottle of cologne, you could find the weight of a bottle.
The Next Level
Let's be more precise. 3.4 fl oz. of cologne or perfume is really 100 ml, or 3.3814 fl oz, or 7.29 grams.
Milliliters to Grams
100 = 78.3 g
110 = 86.1 g
120 = 94 g
125 = 97.9 g
150 = 117 g
Some sources say 12-15% (fluid) of EDP is perfume oil, some say 10-20%. Let's use Medium.com's scale:
Eau de Parfum: 15-20%
Eau de Toilette: 5-15%
Eau de Cologne: 2-4%
Eau de Fraiche: 1-3%
D&G The One EDP is purportedly 80% alcohol, and 20% perfume and water.
Okay, now water is in the mix.
Let's just say this is interesting, and I need a break, so let's call it an article.