Perfume types reflect the concentration of aromatic compounds in a solvent, which in fine fragrance is typically ethanol or a mix of water and ethanol. Various sources differ considerably in the definitions of perfume types. The concentration by percent/volume of perfume oil is as follows:

Perfume extract (Extrait): 15-40% (IFRA: typical 20%) aromatic compounds
Eau de Parfum (EdP), Parfum de Toilette (PdT): 10-20% (typical ~15%) aromatic compounds. Sometimes listed as "eau de perfume" or "millésime".
Eau de Toilette (EdT): 5-15% (typical ~10%) aromatic compounds
Eau de Cologne (EdC): Chypre citrus type perfumes with 3-8% (typical ~5%) aromatic compounds
Splash and After shave: 1-3% aromatic compounds
Perfume oils are often diluted with a solvent, though this is not always the case, and its necessity is disputed. By far the most common solvent for perfume oil dilution is ethanol or a mixture of ethanol and water. Perfume oil can also be diluted by means of neutral-smelling oils such as fractionated coconut oil, or liquid waxes such as jojoba oil.

The intensity and longevity of a perfume is based on the concentration, intensity and longevity of the aromatic compounds (natural essential oils / perfume oils) used: As the percentage of aromatic compounds increases, so does the intensity and longevity of the scent created. Different perfumeries or perfume houses assign different amounts of oils to each of their perfumes. Therefore, although the oil concentration of a perfume in Eau de Parfum (EdP) dilution will necessarily be higher than the same perfume in Eau de Toilette (EdT) from within the same range, the actual amounts can vary between perfume houses. An EdT from one house may be stronger than an EdP from another.

Men's fragrances are rarely sold as EdP or perfume extracts. As well, women's fragrances are rarely sold in EdC concentrations. Although this gender specific naming trend is common for assigning fragrance concentrations, it does not directly have anything to do with whether a fragrance was intended for men or women.

Furthermore, some fragrances with the same product name but having a different concentration name may not only differ in their dilutions, but actually use different perfume oil mixtures altogether. For instance, in order to make the EdT version of a fragrance brighter and fresher than its EdP, the EdT oil may be "tweaked" to contain slightly more top notes or fewer base notes. In some cases, words such as "extrême", "intense" or "concentrée", that might indicate aromatic concentration are sometimes completely different fragrances that relates only because of a similar perfume accord. An example of this would be Chanel‘s Pour Monsieur and Pour Monsieur Concentrée.

Eau de Cologne (EdC) since 1706 in Cologne, Germany is originally a specific fragrance and trademark. However outside of Germany the term has become generic for Chypre citrus perfumes (without base-notes).