No international standard fixes the strength of either label. IFRA, the fragrance industry's standards body, calls "eau de toilette" and "eau de parfum" general descriptors that vary by market and region. By convention an eau de parfum holds more perfume concentrate, typically around 15% against 10% for an eau de toilette, so it usually lasts longer on skin.
The US government doesn't settle it either. The FDA's page on fragrances in cosmetics lists perfume and cologne as cosmetics and says nothing about how strong either must be. Each perfume house draws its own ladder, and the rungs overlap.
How the published ranges compare
Two reference points are worth having side by side: IFRA's typical ranges, which describe common industry practice, and the figures The Perfume Society, a UK consumer organization, gives in its strength guide.
| Strength | IFRA typical range | The Perfume Society |
|---|---|---|
| Eau de cologne (EDC) | 3–8% (about 5%) | 2–4% |
| Eau de toilette (EDT) | 5–15% (about 10%) | 4–8% |
| Eau de parfum (EDP) | 10–20% (about 15%) | 8–15% |
| Parfum or extrait | 15–40% (about 20%) | 15–25% parfum, 20–30% extrait |
Look at the eau de toilette row. A bottle at 10% concentrate sits in the middle of IFRA's EDT range and above the top of The Perfume Society's. Floris, the London perfumer, prints yet another scale, with EDT at 5–15% and EDP at 15–20%. None of them is wrong, because none of them is law.
What IFRA does regulate is safety. Its standards cap how much of each individual material may appear in the finished product. They limit what a perfumer may put in the bottle and say nothing about what the bottle may be called.
A stronger version isn't always the same scent
When a well-known perfume comes in several strengths, the versions are often reformulated. The Perfume Society warns that different concentrations "might feature varying notes and aren't merely weaker or stronger versions of the same scent." If you love someone's EDT, try the EDP on skin before buying it as a gift.
Which lasts longer on skin?
At the same house and in the same family of scents, the eau de parfum wins. Floris gives 6–8 hours for its eaux de parfum and 4–6 hours for its eaux de toilette. Those are one maker's figures, and nobody measures wear time the same way.
The ingredients matter as much as the concentration. The Perfume Society's perfume FAQ describes top notes, usually citrus, herbs and fruit, as lasting around 5–15 minutes, heart notes two to four hours, and base notes four to six hours, adding that "lighter, citrussy scents deteriorate faster than opulent florals." A lemon cologne fades by mid-morning whatever the label says, and a woody eau de toilette can outlast a citrus eau de parfum.
Strength also isn't the same as reach. An extrait "will stay on your skin for far longer than an EDP, but it may not project as much," according to The Perfume Society's comparison of the two. The strongest bottle can be the quietest one in the room.
Skin and application change the result
Dry skin lets perfume evaporate faster, and oilier skin holds it longer. The fix for dry skin is to smooth on an unscented body oil or lotion first, which gives the fragrance "something to 'cling' to," in The Perfume Society's advice on making perfume last. Hair carries scent well too, though a dark-colored perfume can tint light hair, and a spritz on a scarf warms up with your body through the day.
Hold back on reapplying. You may stop smelling your own perfume after 30 or 40 minutes while people around you still can, so ask someone before you spray again.
Why we make orange blossom as an eau de parfum
It's tempting to think a fresh citrus-floral belongs at cologne strength. The drawback is the evaporation curve above: the citrus opening goes first, and a thin formula has little left underneath once it does.
Orange blossom is a heart note, a flower rather than a peel. More concentrate gives that floral heart the weight to carry on after the sparkle of the opening has lifted. That is why all four of our perfumes are eaux de parfum, and why we don't make cologne or EDT versions. Our orange blossom perfume is a soliflore, a scent built around a single flower, rather than a top-heart-base pyramid. We don't publish its exact concentration; given how loosely the terms are used, a single number would tell you less than it seems to.
Orange blossom has a long history as a California scent, which our piece on orange blossom perfume in Southern California's Gilded Age traces. Orange Blossom Noir, Big Red Rose and California Lavender make up the rest of our perfume collection. All four come in 0.5 oz and 1.5 oz sprays, and Orange Blossom and California Lavender also come as a 0.25 oz roller.
To compare two strengths of one perfume, get samples of both, spray one on each wrist in the morning, then smell both after lunch and again at dinner.
Photo by Siora Photography on Unsplash.
