What is the varying degree of strength on Perfumes?

Most people know that fragrances come in varying degree of strength (that has nothing to do with the volume of the fragrance in the bottle), but just what is the difference between Eau de Parfum, Eau de Cologne, After Shave, Eau de Toilette, and other strengths and descriptions?

These terms all refer to the strength of the fragrance, or more specifically, to how much high grade alcohol and/or water has been added to the fragrance oils. Parfum (generally the most concentrated form you can buy) has 15-25% perfume oil dissolved in alcohol. Any mixture with a lower proportion of oil to alcohol is an eau (meaning water).

In order of strength:

Perfume oil or Pure Perfume lasts 6+ hours (15%-30% perfume oil in an oil rather than alcohol base) - Rare. Few fragrances are commercially available in this concentration, and those that are tend to be extremely costly.

Parfum or Perfume lasts up to 4 to 6 hours (15% - 25% -- also sometimes referred to as extract or extrait) - Uncommon. Not many fragrances are commecially available in this concentration, and those that are available are quite costly.

Soie de Parfum lasts 3 to 6 hours (15% - 18% perfume oil) - Not common in commercial release, as above.

Eau de parfum lasts 3 to 5 hours (8% - 15% perfume oil) - Fairly common. Price depends on the brand, the fragrance, etc., but will be more expensive than less concentrated fragrances, naturally. Currently very popular.

Eau de Toilette lasts 3 to 4 hours (4% - 10% perfume oil) - Common. Generally the strongest concentration available in men's fragrance.

Eau de Cologne lasts up to 3 hours (2% - 5% perfume oil) - Common. Was once a very popular concentration, but not as much now, at least in women's fragrances. Still fairly popular in fragrances for men.

After Shave lasts 2 to 3 hours (3% or less perfume oil) - Common. Also note that after shave often has aloe or other balms in it to sooth the skin after a shave, and the alcohol can help close pores. Eau Fraiche lasts 1 hour or less (3% or less perfume oil) - Not very common. Sometimes referred to as "perfumed mist" or "splash". Often alcohol free.

These terms are commonly seen abbreviated, such as EDP for Eau de Parfum, EDT for Eau de Toilette, etc.