Percentages are the language of perfumery, and once they click, a formula stops being intimidating and becomes a precise, repeatable set of instructions. This article explains exactly what the numbers on a perfume formula mean, how concentration works, and how to scale any formula to the batch size you want.
Percentages describe the concentrate
The percentages in a formula always refer to the concentrate — the blend of aroma materials before any dilution. They sum to 100%, with a diluent such as DPG or perfumer's alcohol making up any balance. So a material listed at 8% means it makes up 8% by weight of the concentrate. Every ScentFormulas formula is written this way, which makes it unambiguous and easy to scale.
Why weight, not volume
Perfumery is done by weight because aroma materials have very different densities — a millilitre of one material can weigh noticeably more or less than a millilitre of another. Measuring by weight removes that variable entirely. The happy consequence is that percentage equals grams per 100 g: a material at 8% is simply 8 g in a 100 g batch. That direct relationship is what makes scaling so easy.
Scaling to any batch size
To scale a formula, multiply each material's percentage by your batch size and divide by 100. For a 50 g batch, that 8% material becomes 8 × 50 ÷ 100 = 4 g. For a 10 g test batch it's 0.8 g; for a 1 kg production batch it's 80 g. The ratios never change — only the absolute quantities. Inside your account, every formula includes a live batch calculator that does this instantly for 10 g, 50 g, 100 g, 1 kg or any custom size, so you never have to do the arithmetic by hand.
A practical tip: make small test batches first. A 10 g concentrate batch is enough to evaluate a formula and costs very little in materials. Once you're happy, scale up.
Concentration: from concentrate to finished fragrance
The concentrate is not what you wear — it's far too strong. You dilute it in perfumer's alcohol to a finished concentration, and that percentage determines the fragrance class:
- Eau de cologne: roughly 3–8% concentrate
- Eau de toilette: roughly 8–15%
- Eau de parfum: roughly 15–25%
- Extrait / parfum: roughly 25–40%
Each formula gives a recommended concentration — usually around 20% for an eau de parfum. To dilute, you weigh your matured concentrate and add alcohol to reach the target. For a 20% EDP, 20 g of concentrate is topped up to 100 g total with 80 g of alcohol.
Worked example
Say you have a 100 g concentrate batch and want a 20% eau de parfum. You'll combine your 100 g of concentrate with 400 g of perfumer's alcohol, giving 500 g of finished fragrance at 20% strength. That single 100 g batch of concentrate therefore yields roughly half a kilo of wearable perfume — which is why even a small batch goes a long way.
Pre-dilutions and trace materials
Some materials are so potent they appear at a fraction of a percent. Weighing 0.03 g accurately is impractical, so perfumers pre-dilute these into 10% solutions and weigh ten times the amount. If a formula calls for 0.3% of a material, you weigh 3% of its 10% dilution instead — far easier and more accurate. Our formulas flag which materials to pre-dilute and our beginner guide walks through the technique.
Why the total must sum to 100
When you build or adjust a formula, the percentages must total 100% (we allow a ±0.5 tolerance for rounding). If they don't, your proportions are wrong and the scent won't match the intended balance. This is also why our admin tools and bulk importer validate that every formula's percentages sum correctly before anything is saved — accuracy here is the difference between a faithful reconstruction and a near miss.
Putting it together
Once you internalise three ideas — percentages describe the concentrate, percentage equals grams per 100 g, and concentration is the final dilution in alcohol — a formula becomes completely transparent. You can read it, scale it, and make exactly the quantity you need at exactly the strength you want. From there, the only limit is your palette and your patience. Browse the catalogue and try scaling a formula to a 10 g test batch to see how simple it really is.