Basic Usage:
The Lye Calculator is easy to use. Choose up to eight base oils from the "Base Oils" column, type the amount of each oil you want to use in the "Weight" column, then add any super-fatting oils and their amounts. Click the "Calculate" button and all other fields will be calculated automatically. Remember to click the "Calculate" button if you change or add any numbers. Customize your recipe by entering the name at the top, and entering your preferred liquid. Click the "Print Recipe" button to display a customized, printer friendly version of your new recipe.

Excess Oil %:
Three different values will be displayed for the lye amount that reflect the percentage of leftover oils in your soap. Designing your soap with 0% excess oil is not normally recommended. 5% excess oil is the norm for most soap makers, and makes a relatively mild, yet good-cleansing bar. Use the 10% excess oil amount for a particularly mild soap.

Finding SAP values:
You can find the SAP value of an individual oil by choosing it in the "Base Oils" column, then typing "1" in the "Weight" column. The SAP value of your chosen oil will be displayed in the "Lye (SAP)" column.