Just What Is the Difference Between Perfume, Eau de Parfum, Eau de Toilette, and Cologne?  Shopping for fragrance can be confusing at best, or overwhelming at worst. Not only are there top notes, middle notes, and bottom notes, but whole classes of scents. What’s more, once you’ve decided on a scent, another decision must be made: perfume, eau de parfum, eau de toilette or cologne? Fragrances are available in perfume, eau de parfum, eau de toilette, or cologne form. The main differentiating factor of these is the concentration of aromatic compounds in a solvent – that is, how much fragrance is in the formula’s composition. The more actual perfume concentrate it contains, the longer the scent will last on your skin, and the more expensive the product. Following is a breakdown of these categories. Perfume Perfume, also referred to as perfume extract, is the most concentrated formulation, and is usually the most expensive. It contains 15-30% aromatic compounds. Due to its high amount of aromatic compounds, it also tends to last the longest when applied to the skin. It is usually sold in small bottles of 1 ounce or less. Eau de Parfum Eau de parfum, also called eau de perfume, is the next most concentrated formula, and one of the most popular purchases. It consists of 10-15% aromatic compounds. Eau de Toilette Eau de toilette is also a popular choice, and is less expensive than the perfume or parfum formulations, although its scent will not last as long when applied to the skin. Eau de toilette contains 5-20% aromatic compounds. Cologne, or Eau de Cologne Eau de Cologne originated in Cologne, Germany. Today, it is a generic term that defines a class of scented formulations by its typical concentration of about 2-5%. Cologne products are available for either men or women, and are sometimes mistaken for aftershave, which is actually a formula containing moisturizer, an antiseptic agent, and perfume. In addition, aftershave can be a gel, lotion, or liquid. For any perfume concentration, be sure to keep the bottle tightly sealed and stored in a cool, dry place away from windows or direct sunlight or heat sources to maximize its shelf life. For best results, store opened bottles inside their boxes. Fragrances usually last three years from the date they were manufactured.