Parfum · EDP · EDT · EDC
Fragrance concentration calculator
Find out how strong a blend is, by volume and by weight, and where it sits among parfum, eau de parfum, eau de toilette and cologne. Then dilute or strengthen it to a new strength, or check whether an allergen must go on the label.
- Strength by volume15%3 mL in 20 mL
- Strength by weight16.6%2.7 g in 16.3 g
Within the usual ranges for parfum, eau de parfum and eau de toilette. The names are conventions: one brand's eau de toilette can be stronger than another's eau de parfum.
The same strength in a 50 mL bottle: 7.5 mL concentrate and 42.5 mL alcohol or carrier.
Add 10 mL of perfumer's alcohol
0.34 fl oz. You will have 20 mL at 10%.
- Now20%10 mL, 2 mL concentrate
- After10%20 mL in total
Check your bottle first: 20 mL needs a bottle of at least that size, and a little headroom under the sprayer. Need less? Pour off part of the 10 mL first and scale the addition down in proportion.
- Allergen in the product0.6%4% of a 15% concentrate
- Labelling threshold0.001%leave-on, EU rule
Must be named on the label. At 0.6% of the product it is 600 times the 0.001% threshold for leave-on products.
To stay under the threshold this concentrate could be at most 0.025% of the product, far below perfume strength, so in practice perfumes list their allergens. Repeat the check for each allergen on your supplier's declaration.
Parfum, eau de parfum, eau de toilette, cologne
These names describe how much fragrance concentrate is dissolved in alcohol, but no law or standard fixes them. Brands choose their own strengths and the ranges quoted by different sources overlap, so a strong eau de toilette from one house can out-measure a light eau de parfum from another. The table spans the figures most often quoted; "typical" is the usual centre.
| Name | Quoted range | Typical | In 50 mL at typical |
|---|---|---|---|
| Parfum (extrait de parfum) | 15–40% | about 20% | 10 mL + 40 mL |
| Eau de parfum (EDP) | 10–20% | about 15% | 7.5 mL + 42.5 mL |
| Eau de toilette (EDT) | 5–15% | about 10% | 5 mL + 45 mL |
| Eau de cologne (EDC) | 2–5% | about 3% | 1.5 mL + 48.5 mL |
| Eau fraîche, splash or body mist | 1–3% | about 2% | 1 mL + 49 mL |
How to use it
What strength is it? Enter the concentrate and the alcohol or carrier you used, in millilitres, drops, grams or fluid ounces. You get the strength by volume, the usual way perfumers talk about it, and by weight, the way IFRA limits and EU allergen thresholds are written. Because oils are denser than alcohol, the weight figure comes out a little higher. The scale shows which conventional names fit.
Dilute or strengthen. Enter how much you have, its strength now and the strength you want. To make it weaker you add only alcohol or carrier; to make it stronger you add only concentrate made to the same recipe. Enter 100% for a neat concentrate you have not diluted yet.
Allergen labelling. Multiply the allergen's share of your concentrate by the concentrate's share of the product. In the EU a listed fragrance allergen must be named on the label above 0.001% in leave-on products and 0.01% in rinse-off products.
Worked examples
3 mL of concentrate in 17 mL of alcohol is 15% by volume, an eau de parfum. With densities of 0.9 and 0.8 g/mL that is 16.6% by weight. To turn 10 mL of a 20% parfum into a 10% eau de toilette, add 10 mL of alcohol and you have 20 mL. A concentrate with 4% linalool used at 15% puts 0.6% linalool in the perfume, 600 times the leave-on threshold, so it must be listed.
Selling what you make
Once a perfume is sold or given away as a product in the EU, it is a cosmetic under Regulation (EC) No 1223/2009. That means a responsible person in the EU, a safety report signed by a qualified safety assessor, notification on the EU's Cosmetic Products Notification Portal before it goes on sale, and a full label. Regulation (EU) 2023/1545 lengthened the list of fragrance allergens that must be named individually to more than 80 entries: products newly placed on the market have had to follow it since 31 July 2026, and products already on sale must do so by 31 July 2028.
Fragrance oil suppliers usually provide an IFRA certificate, which gives the most of that oil each product category can contain (fine fragrance is category 4), and an allergen declaration listing the percentage of each allergen in the oil. For blends of essential oils you combine those figures yourself, which the allergen tab helps with. Other countries have their own rules, so check where you sell.
Stronger is not always better
- A higher strength puts more of every material on your skin. Check each oil's limit before you strengthen a blend, especially cold-pressed citrus oils, which can burn skin in sunlight above their maximum.
- Patch test a new strength before wearing it widely, and stop if the skin turns red, itchy or swollen.
- Perfumer's alcohol is highly flammable. Keep it away from flames and heat, and keep every bottle away from children and pets. Never drink perfume or essential oils.
Questions
What is the difference between eau de parfum and eau de toilette?
Mainly strength. An eau de parfum usually holds about 10 to 20% fragrance concentrate and an eau de toilette about 5 to 15%, so the two overlap. The names are conventions rather than legal definitions, and some brands also change the formula between versions.
Why does my blend have two strengths?
One is by volume and one by weight. Perfumers usually measure by volume, but IFRA limits and EU allergen thresholds are percentages by weight. Fragrance oils are denser than alcohol, so the weight figure is a little higher.
How do I make my perfume weaker?
Add only alcohol (or the same carrier oil). The new strength is the old strength times the old volume divided by the new volume, so doubling the volume halves the strength. The "Dilute or strengthen" tab works out the amount.
Does a stronger concentration last longer?
Often, but not always. How long a scent lasts depends a great deal on its materials: a light citrus fades quickly even at parfum strength, while woods, resins and musks linger even in an eau de toilette. Skin, climate and how much you apply matter too.
Do I need to list allergens on a perfume I make for myself?
Labelling rules apply to products sold or given out as cosmetics. For your own bottle there is no legal duty, but knowing what is in it helps if your skin reacts. The allergen tab shows how quickly allergens pass the threshold.
Sources
- Wikipedia, Perfume, concentration levels: parfum 15–30% (typically about 20%), eau de parfum 15–20% (about 15%), eau de toilette 5–15% (about 10%), eau de cologne 2–3%, eau fraîche 3% or less, and the note that definitions differ between sources. Retailers' guides quote wider ranges (parfum up to 40%, eau de parfum from 10%, cologne up to 5%), which the table includes.
- Regulation (EC) No 1223/2009 on cosmetic products, EUR-Lex: Annex III and the 0.001% / 0.01% labelling thresholds, responsible person, safety report and notification.
- Commission Regulation (EU) 2023/1545, EUR-Lex: the extended list of fragrance allergens and its transition dates.
- International Fragrance Association, IFRA Standards Library: maximum use levels by product category.
- PubChem, Ethanol (CID 702): density 0.789 g/mL at 20 °C and flash point about 13 °C.