In short
A fragrance is bought by the kilogram and paid for per unit sold. Cost in use — cost per kg × dose × fill — is the figure that matters, and it can reverse a comparison: a cheaper oil that needs a higher dose to perform can cost more per bottle. Beyond the formula sheet sit costs it never shows: minimum order quantities, losses in compounding and filling, and the effort of qualifying a new material.
What you will learn
- Calculate cost in use per finished unit from cost per kg, dose and fill
- Find the break-even dose at which a cheaper oil stops being cheaper
- Include losses, minimum order quantities and qualification effort in the comparison
- Present an economic comparison a client can check
Before this lesson: Supplier Qualification and Raw-Material Specifications, Cost Calculation for the Capstone, Optimization Under Constraints: Cost and Composition
Before you start
This builds on the capstone cost calculation, the optimization lesson and supplier qualification. All figures here are invented for the arithmetic, in currency units.
The calculation
Cost in use = Ckg × mfill × d, with the fill in kg and the dose as a fraction.
| Oil | Cost per kg | Working dose | Cost per unit |
|---|---|---|---|
| A | 120 | 18% | 1.08 |
| B | 80 | 24% | 0.96 |
| B, if it needs 30% | 80 | 30% | 1.20 |
The break-even dose for B is 1.08 ÷ (80 × 0.05) = 27%. Below it B is cheaper; above it, dearer. Which dose B needs is a performance question, decided by a controlled comparison at equal perceived strength, not by its price.
What the formula sheet hides
- Losses. Compounding, filtration, line flushing and filling lose material; a few percent on a costly oil is real money. Measure your own yield.
- Minimum order quantities. A material needed at 2 kg a year and sold in 25 kg lots costs the whole lot unless it is used elsewhere before its re-test date.
- Qualification. A cheaper supplier needs a specification check, samples, a blind comparison and requalification of every product it enters.
- Price volatility. Naturals move with harvests; date every price and check the formula's sensitivity to its most volatile material.
Presenting it
Show cost in use at the working dose, the break-even dose, the losses assumed, and the date of every price, so the client can recheck it. A comparison that hides its assumptions invites the client to distrust all of it.
Limitations
Cost in use ignores what the fragrance contributes to selling the product, which is the point of a good fragrance; the cheapest oil is rarely the brief. It also depends on dose decisions that interact with performance and regulation: a higher dose can bring a restricted material closer to its limit.
Research application
How does perceived strength scale with dose for two oils of different character? Measuring both at matched perceived intensity, and finding the dose ratio, is the empirical half of every break-even calculation, and rarely done carefully.
Practical exercise: Compare two concentrates in use
- Take two versions of one fragrance (an original and a cost-reduced one) with their dated costs per kg.
- Find the dose at which the cheaper version matches the original's perceived strength, by a blinded comparison at three doses.
- Calculate cost in use at both working doses and the break-even dose.
- Add losses (measured or stated), minimum-order effects and qualification effort, and write a recommendation.
You have done this well if the working doses come from a blinded comparison rather than assumption, every price is dated, the break-even dose is calculated correctly, and the recommendation states the assumptions that would change it.
Common mistakes
- Comparing prices per kg. Compare per unit at working dose.
- Assuming equal doses. Measure perceived strength.
- Forgetting the regulatory effect of a higher dose. Recheck restrictions at the new dose against current sources.
Key terms
- Cost in use
- The cost of the fragrance in one finished unit: cost per kg of concentrate × dose × fill weight, before other components.
- Break-even dose
- The dose at which a cheaper-per-kg concentrate costs the same per unit as a dearer one at its own dose.
- Minimum order quantity
- The smallest amount a supplier will sell. When it exceeds what a product needs, the unused remainder is a real cost.
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.