Free calculator
Perfumery unit converter
An ounce by weight and a fluid ounce are different things, and an American fluid ounce is not a British one. This converts inside weight and inside volume exactly, and crosses between the two only through a density you supply.
Two kinds of unit, and one bridge between them
Grams, kilograms, ounces and pounds measure weight. Milliliters, liters and fluid ounces measure volume. Inside each kind the conversions are exact, because the units are defined against each other. Between the two kinds the only bridge is density, the weight of one milliliter of the particular liquid in front of you.
The exact definitions
- One ounce by weight is exactly 28.349523125 g.
- One pound is exactly 453.59237 g.
- One US fluid ounce is exactly 29.5735295625 ml.
- One UK fluid ounce is exactly 28.4130625 ml.
100 ml is 3.3814 US fluid ounces, or 3.5195 UK fluid ounces. At a density of 0.87 g/ml, 100 ml of that liquid weighs 87 g, which is 3.0688 ounces by weight.
Where ounces go wrong
An ounce of weight and a fluid ounce of volume share a name and nothing else. They are only close for liquids near the density of water, and most aroma materials and every alcoholic perfume are not.
The fluid ounce is not even one unit. An American fluid ounce is about four percent larger than a British one. A recipe, a bottle or a price list written in fluid ounces does not say which unless it tells you, and the difference is enough to put a run of bottles short.
The density has to be yours
Water is 1.0 g/ml. A finished alcoholic perfume is typically somewhere around 0.85 to 0.90. Aroma materials range well either side of both. None of those is your liquid.
Measure it once: weigh a known volume at a known temperature and divide the weight by the volume. It takes a couple of minutes and it stays true for that liquid, which turns every conversion that depends on it from an estimate into a number.
What this calculator does not do
It does not guess a density, so without one it will not turn milliliters into grams or grams into milliliters. It does not correct for temperature, which moves the density of a liquid a little. And it does not tell you which fluid ounce a label meant.