Tools / Dilution calculator
Dilution calculator: stock to target concentration
Use this when a raw material arrives stronger than the concentration you want in a premix or a finished water phase. Enter the stock and target concentrations plus one volume. The missing volume follows from C1×V1 = C2×V2.
The calculator only rearranges C1V1=C2V2. It does not propose a safe or effective cosmetic use level.
Result is C1V1=C2V2 arithmetic, not a recommended use level.
- Stock volume
- 10 mL
- Diluent volume
- 40 mL
- Final volume
- 50 mL
- Dilution factor (C1/C2)
- 5
Confirm units on the TDS or COA before you dilute. A “2% solution” and a “2% active in a 20% solution” are different starting points. Do not treat this result as a preservative or active recommendation.
How the calculation works
Concentrations are first converted to a common percent scale: 10 mg/mL = 1%, 10 000 µg/mL = 1%, 10 000 ppm = 1%. Volumes are converted to millilitres. To prepare a target volume V2 at concentration C2 from a stock C1, the stock volume is V1 = (C2 × V2) ÷ C1. The diluent volume is V2 − V1. To ask the inverse question — how large a batch you can make from a known stock aliquot — the page solves for V2 instead.
Worked example
A laboratory holds a 10% stock and wants 50 mL at 2%. V1 = (2 × 50) ÷ 10 = 10 mL of stock, plus 40 mL of diluent. The same 10 mL of stock could also make 100 mL at 1%. These numbers illustrate the equation. They are not a suggested use level for any named active, peptide, or preservative.
Common mistakes
Mixing units (percent against mg/mL) without converting is the fastest way to a ten-fold error. Another is diluting below the solubility or preservation limit of the finished system and assuming the math still “approves” the formula. A third is using mass for one side and volume for the other when density is not ~1 g/mL. If C2 is higher than C1, this is concentration, not dilution — the calculator refuses that path.
When the datasheet still wins
Supplier documents decide whether the grade is already a solution, what solvent it sits in, the approved addition temperature, and the documented use window. Microbiological validation and stability work are not replaced by a dilution identity. If the COA and the bottle label disagree, stop and resolve that before weighing.