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The Sage Lye Calculator

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The Sage Lye Calculator is a vital tool for soap makers, designed to simplify the process of calculating the precise amount of lye (sodium hydroxide, NaOH) required to saponify various types of fats and oils in soap making. This calculator helps ensure that the soap-making process is safe and that the end product is of high quality and gentle on the skin.

Purpose and Functionality of The Sage Lye Calculator

The main purpose of the Sage Lye Calculator is to determine the exact amount of lye needed to convert fats and oils into soap, a process known as saponification. Each type of fat or oil used in soap making has a specific saponification value, which is the amount of lye required to saponify a given amount of that oil. The calculator also accounts for superfatting—a technique used to enhance the moisturizing properties of the finished soap by leaving a portion of the oils unsaponified.

How The Sage Lye Calculator Works

Inputs Required:

  • Type of Fat or Oil: Each oil requires a different amount of lye to saponify.
  • Amount of Each Fat or Oil: Typically measured in grams or ounces.
  • Superfatting Percentage: This optional percentage represents the amount of oil that will remain unsaponified, adding extra moisturizing properties to the soap.
  • Lye Concentration or Water:Lye Ratio: Determines the amount of water mixed with lye, affecting the soap’s curing time and texture.


  1. Calculate the Total Lye Required:
    • Multiply the amount of each oil by its saponification value.
    • Sum these amounts to get the total lye required.
  2. Adjust for Superfatting:
    • Reduce the total lye amount by the superfatting percentage.
  3. Calculate the Amount of Water:
    • If using a water:lye ratio, multiply the total amount of lye by this ratio.
    • If using a lye concentration percentage, use the formula: Water = Lye / (Lye Concentration/100 - 1).

Example of Using The Sage Lye Calculator

Let’s assume you are making soap with 100 grams of coconut oil, which has a saponification value of 0.190. You decide to use a 5% superfatting level and a water:lye ratio of 2:1.

  • Lye Required (without superfatting):
    • 100 grams × 0.190 = 19 grams of lye
  • Adjusting for Superfatting:
    • 19 grams - (5% of 19 grams) = 18.05 grams of lye
  • Calculate Water:
    • 18.05 grams × 2 = 36.1 grams of water

Information Table: Common Oils and Their Saponification Values

Oil TypeSaponification Value (grams of lye per gram of oil)
Coconut Oil0.190
Olive Oil0.134
Palm Oil0.141
Almond Oil0.136
Shea Butter0.128


The Sage Lye Calculator is an indispensable tool for soap makers, enabling them to create safe and effective soap bars tailored to specific skin types and preferences. By accurately calculating the amount of lye needed, soap makers can ensure that their products are not only effective but also safe and moisturizing. This calculator not only enhances the quality of the soap produced but also helps in experimenting with different oil blends and superfatting levels to achieve desired soap characteristics.

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