Perfume cost per hour.

Worked example

Perfume A is 100 ml at $150, so $1.50 per ml; 4 sprays of 0.1 ml is 0.4 ml a wear, $0.60, and at 6 hours of scent that is $0.10 per hour. Perfume B is 50 ml at $60, $1.20 per ml, so $0.48 a wear, but only 3 hours of scent makes it $0.16 per hour. A $20 monthly budget buys 20 x (6 / 0.60) = 200 hours of A or 20 x (3 / 0.48) = 125 hours of B.

How it works

Price per ml = price / size. Cost per wear = sprays x ml per spray x price per ml. Cost per hour = cost per wear / hours of scent. Hours per budget = budget x hours / cost per wear. Hours of scent are your own estimate, so use the time you can actually smell it, not the time it technically lasts.

What this is not. Longevity is subjective: skin chemistry, weather, application spot and your own scent fatigue all change it, and there is no standard way to measure it. Cost per hour ignores how much you like the scent, which usually matters more.

Sources and basis: pure arithmetic on the numbers you enter; no published figure is used, and any default marked as an assumption or rule of thumb is not a published standard.

FAQ

Is expensive perfume worth it per hour?

Sometimes. If it lasts much longer on you it can cost less per hour than a cheaper scent. The result shows both numbers side by side.

How do I estimate how long a perfume lasts?

Spray it in the morning and note when you can no longer smell it on your wrist or clothes. Use that time; a friend's opinion may differ.

What counts as the cost per wear?

Sprays per wear x ml per spray x price per ml. The default 0.1 ml per spray is an assumption you can change.

Can I compare more than two perfumes?

Run the calculator again with each pair. Perfume A can stay as the one you are measuring everything against.