Calculating Phenoxyethanol in Cosmetic Formulations

When formulating cosmetics, all ingredients, including preservatives like Phenoxyethanol, should be included in the total percentage calculation of the formula. This is the standard practice for accurate formulation and is essential for commercial production.

However, as mentioned in the staff reply, for small-scale home use, because preservatives like Phenoxyethanol are used in very small amounts (typically 0.5% to 1.0% of the total formula), some people find it simpler to calculate the percentage based on the weight of the finished formula before adding the preservative. They then add the required percentage of the preservative based on that weight. While this method is less precise than including it in the initial total calculation, it is a common shortcut for personal use and generally does not cause significant issues due to the low concentration.

For professional or commercial formulations, always include Phenoxyethanol as part of the total 100% calculation of your formula.