Cosmetics Preservative Dosage Calculator
Calculate the precise amount of cosmetic preservative needed for water-containing formulations to prevent microbial contamination.
Results
What is it?
Any cosmetic formulation containing water (emulsions, toners, shampoos, creams) requires a broad-spectrum preservative to prevent bacterial, fungal, and mould growth. Preservatives are dosed as a percentage of total formula weight.
How to use
Enter your total batch weight and select your preservative system. The calculator outputs the exact gram weight to add. Always add preservatives at the recommended usage rate � too little is ineffective, too much can be irritating.
Example scenario
For a 200 g face cream using Phenoxyethanol at 0.75%: add 1.5 g of preservative. For a natural lotion using Leucidal Liquid at 3%: add 6 g per 200 g batch.
Pro tip
Conduct challenge testing (microbial efficacy testing) on new formulations. Add preservatives during the cool-down phase below 40�C to avoid degradation. pH also affects preservative efficacy � phenoxyethanol works best at pH 3-8.