In short
To make a dilution, tare a clean vial, weigh in the material, then add solvent up to the total weight. For 10 g of a 10% dilution, that is 1 g of material and 9 g of solvent. Label it with the material, strength, solvent and date. You will use dilutions like this for smelling and for accurately weighing small amounts.
What you will learn
- Calculate what to weigh for a dilution of any strength
- Make a 10% dilution by weight and step it down to 1%
- Label a dilution so that it stays usable and safe
Before this lesson: Your First Weighing Practice
Why perfumers dilute
- To smell properly. Most materials are easier to read at 10% or lower, as you saw in how to smell raw materials.
- To weigh small amounts. If 0.05 g of a material is too small to weigh, 0.5 g of a 10% dilution contains the same amount of material.
- To tame strong materials. Some are unusable until they have been diluted well down.
- To save money. A small amount of a costly material lasts a long time.
The one equation
Everything in this lesson comes from a single relationship, by weight:
material to weigh = total wanted × strength wanted ÷ strength of what you are weighing
The rest of the total is solvent. Here it is at work:
| You want | Starting from | Weigh | Add solvent |
|---|---|---|---|
| 10 g at 10% | Neat (100%) | 10 × 10 ÷ 100 = 1 g | 9 g |
| 25 g at 5% | Neat (100%) | 25 × 5 ÷ 100 = 1.25 g | 23.75 g |
| 10 g at 1% | A 10% dilution | 10 × 1 ÷ 10 = 1 g | 9 g |
| 20 g at 0.1% | A 1% dilution | 20 × 0.1 ÷ 1 = 2 g | 18 g |
The most common beginner error is adding 10% of the solvent: 1 g in 10 g of solvent is 1 ÷ 11 = 9.09%, not 10%. The percentage is of the total. The reference guide to perfume dilution calculations covers harder cases, including changing a dilution inside an existing formula.
Calculators
Work a few by hand first, so you can spot a wrong answer. Both of these run in your browser and send nothing anywhere.
Make a dilution
What to weigh for a dilution of a given strength. Weight, not volume.
How much pure material is in it?
The pure material carried by a weight of diluted material.
The method
- Prepare. Read the material's SDS, put on gloves and glasses, and clear your workspace of ignition sources.
- Label first. Write the label before you start, so that nothing unlabeled ever exists on your bench.
- Tare your clean vial on the scale.
- Add material slowly to the target. Write down the actual weight.
- Add solvent up to the total. Thick materials dissolve more easily if the material goes in first and you add solvent afterward.
- Cap and mix by gentle swirling until it is clear. Solids can take time. Our guide on dissolving solid aroma chemicals can help.
- Complete the label and your log. Correct the stated strength if your weights landed slightly off.
A label that does its job
Every dilution needs at least this, in writing that will survive contact with alcohol:
Bergamot oil, 10% in ethanol · 31 Oct 2026 · Lot 1234
The strength is the most important part. A bottle marked only with the material name will one day get into a formula as if it were neat, and the formula will be wrong by a factor of ten.
Which solvent?
For study dilutions, perfumer's alcohol is the common choice, because it evaporates and leaves the material to be smelled. Some materials are also commonly diluted in dipropylene glycol or similar solvents. These stay behind on the strip, and they may suit materials that dissolve poorly in alcohol. Whichever you use, record it, since a solvent is an ingredient in your formula too.
What this means for a formula
A dilution in a formula brings solvent along with it. If a formula calls for 2 g of a 10% dilution, only 0.2 g of it is the material. This will matter a great deal in Level 5, and it is exactly what absolute and relative percentage are for. The RUŌOD Lab app stores a dilution with each formula line and works out the pure material for you, although you should understand the sum first.
Practical exercise: Make a 10% and a 1%
Choose an inexpensive, thin material such as an orange, lemon or lavender essential oil. Use perfumer's alcohol, and work with the precautions from the safe handling lesson.
- Calculate 10 g of a 10% dilution on paper. Write the two weights.
- Label a vial, then make the dilution. Record the actual weights and work out the true strength. For example, 1.02 g in a 10.05 g total is 10.15%.
- Now calculate and make 10 g of a 1% dilution from your 10%.
- Smell a strip of each, along with a strip of plain alcohol. Write how the character changes between 10% and 1%.
- Check your sums with the calculators on this page.
- Enter both dilutions in your log.
You have done this well if your weights and calculator check agree, both dilutions are labeled and logged with date and solvent, and your notes describe a change you actually smelled.
Common mistakes
- Treating the percentage as a share of the solvent. It is a share of the total.
- Mixing by volume with a syringe. A 10% by volume is not 10% by weight, because densities differ.
- Leaving the strength off the label. This causes the most serious errors later.
- Making large batches. A small batch that you finish is fresher than a large one that sits and ages.
Safety
Alcohol is highly flammable and neat materials can harm skin and eyes, so follow the safe handling lesson. These dilutions are for smelling on paper. They are not for use on skin, and a dilution does not make a material safe to wear.
Key terms
- Dilution
- A material mixed with solvent, stated as the percentage of material in the total weight.
- Stock solution
- A dilution kept ready to use, so that small amounts of a material can be weighed accurately.
- Perfumer's alcohol
- Ethanol prepared for perfumery use, commonly the solvent for study dilutions.
- Dipropylene glycol
- A nearly odorless solvent, often shortened to DPG, used to dilute some materials and sold with some compounds.
Knowledge check
Written and reviewed by the RUŌOD Lab team. This is general education, not legal, regulatory, medical or safety advice. Example dilutions and exercises are for learning, are not validated products, and have not been safety-assessed. Completing a lesson confers no qualification. How we check these lessons.