Sillage, Projection and Longevity: Three Words, Three Meanings

By Mahdi MST · Updated 2026-09-22 · 8 min read

Three words get used interchangeably in fragrance discussion, and they describe three genuinely different things. Worse, two of the three cannot be pinned to a number that holds up in ordinary conditions, and they are still often quoted in numbers.

This matters because it is the difference between a claim you can act on and a claim that sounds precise and means nothing. Here is what each word means, and why Accord Twin's own bottle data carries one figure and not three.

What is the difference between sillage, projection and longevity?

Sillage, projection and longevity answer three different questions about the same spray.

Longevity is duration. You spray, and at some later point you can no longer detect it up close. That gap is the number.

Projection is reach at an instant. A fragrance with strong projection fills the space around you, and how far it reaches changes as the wear goes on.

Sillage is French for wake, as in the trail a boat leaves in water. It describes the scented path left behind a person in motion. It is the most evocative of the three and the least measurable.

A fragrance can be high in one and low in another. Something can sit very close to the skin for nine hours, or fill a room for two and then vanish.

Why can projection and sillage not be measured honestly?

Projection and sillage cannot be measured honestly because both depend on conditions that change constantly and are not properties of the fragrance at all.

Air movement is the obvious one. The same spray behaves differently in a still office, a moving train, and outdoors in wind. Temperature matters, because heat speeds evaporation. Humidity matters. The material you sprayed onto matters, since skin and fabric release scent at different rates. How much you applied matters too.

Then there is the observer problem. Projection and sillage are things other people experience, and other people's noses vary, adapt, and are usually occupied with something else. There is no fixed listener standing at a fixed distance.

Longevity has the same complications in principle, but it degrades gracefully. A range of hours from the same starting point on the same skin is a rough but genuinely useful figure. Distance in feet, quoted from an armchair, is not.

What can be measured is evaporation. Schwarzenbach and Bertschi of Givaudan sampled the air just above the skin in 2001 and tracked how a fragrance thinned out over hours, which is a laboratory result rather than a number from a wrist.

How precise is the vocabulary these terms come from?

The words used to describe fragrance are nowhere near as standardised as the numbers suggest.

The Accord Twin corpus of 107,044 fragrances contains 4,487 distinct note names, and the average release lists about nine of them. Note lists have also thinned: 1980s releases carry 12.70 listed notes on average against 9.50 in the 2020s.

That matters for any measure built on top of them. A vocabulary of four and a half thousand loosely-defined terms, applied by marketing departments rather than to a standard, is not a measuring instrument. It is the reason Accord Twin publishes one wear figure and declines to publish a projection or sillage score at all.

What figure does Accord Twin actually publish?

Accord Twin publishes one figure per bottle, typical wear hours, and nothing else about how a fragrance performs.

Only 36 of the 122 bottles on the list carry a wear figure, and those figures run from around 3 hours at the short end to around 9 hours at the long end. Sol de Janeiro Cheirosa '62 Mist at $39 is the shortest at around 3 hours, which is unsurprising for a mist rather than an EDT or EDP. Four bottles reach around 9 hours in the full ranking by wear time: Tom Ford Tobacco Vanille at $300, Nishane Hacivat at $240, Frederic Malle Portrait of a Lady at $295 and Lattafa Khamrah at $49.99.

Accord Twin deliberately does not publish a projection rating, a sillage rating, or a star score for either. Not because they do not matter to how a fragrance feels, but because the numbers would be invented, and an invented number is worse than no number.

It looks like evidence.

If you see a site quoting projection in feet or sillage out of ten, ask how it was measured, and whether the answer names a method.

Does concentration decide how long a perfume lasts?

Concentration influences how long a perfume lasts, and the size of that influence has been counted rather than assumed: across 1,052 bottles where the label and the wear votes were both recorded, stepping from an eau de toilette up to an eau de parfum raises the share of long-lasting votes by about 14 points.

That is a real effect and a weak guarantee. The two oil ranges overlap at 15 percent, so the strongest eau de toilette on a shelf can hold more oil than the weakest eau de parfum beside it.

The Accord Twin list shows the same shape. Its ten eaux de toilette with a wear figure average about 5 hours and its 24 eaux de parfum about 6.9, and the single extrait, Nishane Hacivat, sits at the top at around 9 hours.

Ulta Beauty's own guide puts extrait de parfum at the top of the concentration ladder, which is the industry's framing rather than a measurement.

Does a higher concentration mean stronger sillage?

A higher concentration is often assumed to mean stronger sillage, but sillage has no honest measurement, so that part of the claim cannot be checked. Concentration describes how much perfume oil is in the alcohol, and from lightest to heaviest the labels on the Accord Twin list are Mist, EDT, EDP and Extrait.

What the wear figures can check is whether concentration always wins on longevity, and it does not. Dior Sauvage, an eau de toilette at $135, is listed at around 6 hours, an hour more than five eaux de parfum, including Lattafa Yara at $44.99 and Juliette Has a Gun Not a Perfume at $210. Price does not settle it either: Lattafa Khamrah at $49.99 carries more than twice the wear figure of Creed Silver Mountain Water at $360. Its dates, vanilla and praline make it one of the gourmand bottles on the list.

How can you judge projection and sillage for yourself?

Judge projection and sillage by testing on your own skin, in the setting you actually care about, and by asking someone else.

Spray the amount you would genuinely wear, not a full arm's worth. A decant gives you enough for weeks of that kind of testing. Then check at intervals, and remember that your own nose adapts within minutes to anything sitting close to you, which is why a fragrance can seem to vanish when it has not, as the guide to making perfume last longer explains.

For projection and sillage specifically, you need a second person, because by definition you cannot perceive your own trail. Ask a colleague at the end of a meeting or a friend across a table. One honest answer from someone else is worth more than any published rating.

Do it in the conditions that matter to you. If you want a work fragrance, test it at work, not at home on a Sunday, because air movement and temperature change the result.

How much can a published wear figure tell you?

A published wear figure tells you less than its neat single number suggests: Accord Twin lists one typical figure per bottle, rounded to the hour, and holds no data on the skin, climate or number of sprays behind it.

The vote-based figures have their own limit. The 1,052-bottle comparison above rests on community wear votes, which are people's reports of how long a bottle lasted on them, not a stopwatch on a wrist, and those 1,052 bottles are about 1 percent of the 107,044 records in Accord Twin's corpus. Coverage on the list is thin too: 86 of the 122 bottles carry no wear figure at all. And Accord Twin has never smelled any of them, so every figure here is published or voted, never tested.

Your own nose is the loosest part of it. A 1996 study found that people stop registering an odour they live with, so a fragrance can still be there long after you have stopped noticing it.

Which matters more when you are choosing a fragrance?

Longevity usually matters more when choosing a fragrance, because it is the one of the three that changes what a bottle costs you per day.

Longevity determines whether you need to carry the bottle and reapply during the day, which is a practical daily cost. It is also the figure most connected to value, since a fragrance you must apply twice is effectively twice the price per day of wear.

Projection and sillage matter mostly at the extremes. If a fragrance is so loud that it fills a lift, that is a real problem in an office. If it sits so close that only someone hugging you would notice, that is a real problem on a night out. In between, they are a matter of preference rather than function.

The practical order is note first, then hours, then test the reach yourself. The note list tells you whether you are likely to like it. The hours tell you whether it fits your day. Only your own skin and an honest friend can tell you the rest.

Prices here are the figures Accord Twin lists, last checked September 2026. They are a reference for comparing bottles, not one shop's till: the same bottle moves with size and retailer, so check the shop before buying.