The logbook for people who make perfume.

In its shortest form, four steps: decide the concentration (staying under the fragrance oil's IFRA limit, typically in the 18 to 30 percent range), work out the oil and base quantities for your bottle volume, add the oil first and then the base and mix, then leave it to macerate somewhere dark and cool. Example: a 50 millilitre bottle at 25 percent by volume uses 12.5 millilitres of oil and 37.5 millilitres of base. The base can be a premixed perfume base or an alcohol, water and fixative blend you build yourself.

Essentially fragrance oil, a base (a premixed base or perfumer's alcohol), a precise scale reading to 0.01 grams, syringes or pipettes, dark glass bottles and labels. Do not use plastic containers; fragrance oil at high concentration affects plastic over time.

Perfume uses pure ethanol, that is, denatured perfumer's alcohol. Pharmacy ethyl alcohol is usually 70 percent, so it contains water and will not give the same result. Methylated spirits must never be used, as they can contain methanol.

The blend has not finished macerating. In the first days the sharp top note of the alcohol dominates; after two to four weeks resting somewhere dark and cool that note recedes and the composition settles.

There are three common reasons: the concentration is too low, the blend has not rested long enough, and there is no heavy component holding the bottom of the composition. A fixative, a woody floor such as Iso E Super, or resinous materials like benzoin and vetiver improve longevity noticeably.

The upper bound is set by the fragrance oil's IFRA limit and you need to stay under it. Conventional ranges are around 3 to 8 percent for cologne, 8 to 15 percent for EDT, 15 to 22 percent for EDP and 22 to 30 percent for parfum. If the limit does not allow it, staying lower is correct rather than forcing those ranges.

Working at 25 percent by volume, a 50 millilitre bottle needs 12.5 millilitres of fragrance oil and 37.5 millilitres of base. If you weigh in grams, the oil's density of roughly 0.95 g/ml means 12.5 millilitres corresponds to about 11.9 grams. At 20 percent the same bottle uses 10 millilitres of oil.

In a volumetric calculation the percentage is read in millilitres; in a gravimetric one it is read in grams. Because the components have different densities, the same percentage corresponds to different amounts in the two methods. Professional perfumery works by weight as standard; volumetric work is also common at home.

With an average density of 0.95 g/ml, 1 gram of fragrance oil is about 1.05 millilitres and 1 millilitre is about 0.95 grams. The conversion is millilitres equals grams divided by 0.95. On that basis 10 grams is 10.53 millilitres, 50 grams is 52.63 millilitres and 100 grams is 105.26 millilitres. Real density varies between 0.85 and 1.05 g/ml depending on the composition.

Yes. The reverse calculation takes the amount of oil you have and your target concentration, then shows the total blend volume, how many bottles it makes and what is left over. For example, 50 millilitres of oil at 25 percent gives 200 millilitres of blend — exactly four 50 millilitre bottles.

Esansmatik is a concentration calculator, formula notebook and cost assistant for people who make perfume at home. You record each perfume's concentration house by house; enter a bottle size and it shows the fragrance oil and base you need in both millilitres and grams. It also keeps a note for every batch, works out the cost and profit per bottle, and lets you open selected formulas to other perfumers with a link.

Every feature is free right now and we do not ask for card details. If a paid plan arrives later we will announce it in advance; until then everything you enter stays yours.

Yes. The batches you select are collected on your own share page, and whoever you give the link to can see it without signing in. You decide which batches appear and whether the formula itself is visible. There is no user search in the app; only the person you give the link to can find you, and share pages are closed to search engines.