Calculating Ingredient Usage with Percentage Concentration

Hello! You're asking how to calculate the amount of a product to use when it has a specific concentration of the active ingredient, based on the desired final concentration in your formulation. This is a common calculation in formulation.

Let's use your example: You have Cetrimonium Chloride (CETAC 30%) and you want the final formulation to contain 0.25% active CETAC.

The correct way to calculate this is using a simple proportion based on the concentration of the active ingredient.

Formula:

Amount of Product Needed = (Desired Concentration of Active Ingredient / Concentration of Active Ingredient in the Product) * Total Amount of Final Formulation

If you want to know the percentage of the product needed in your final formulation (assuming your total formulation is 100% or 100 units), the formula becomes:

Percentage of Product Needed = (Desired Concentration of Active Ingredient / Concentration of Active Ingredient in the Product) * 100%

Applying to your example:

• Desired Concentration of active CETAC = 0.25%
• Concentration of active CETAC in the product (CETAC 30%) = 30%

Percentage of CETAC 30% Product Needed = (0.25% / 30%) * 100%
= (0.25 / 30) * 100%
≈ 0.008333 * 100%
≈ 0.8333%

So, to get 0.25% active CETAC in your final formulation, you need to use approximately 0.8333% of the CETAC 30% product.

Regarding the calculation method you provided:

The method "From 30 to 100, multiply by 3.33" is not the standard way to explain this calculation. While multiplying 0.25 by 3.33 (which is approximately 100/30) gives a result close to the correct answer (0.8325% vs 0.8333%), the explanation itself is confusing and doesn't clearly illustrate the principle of dilution based on concentration ratios. The standard method is to use the ratio of the desired concentration to the product's concentration, as shown above.

In summary, to achieve 0.25% active CETAC using a 30% CETAC product, you should use about 0.8333% of the 30% product in your formulation.