The only international non-profit trade association promoting the benefits of handcrafted soaps and giving a voice to the handcrafted soapmaker.

Lye Calculator Help & Directions

Overview

Return to Regular Lye Calculator or Advanced Lye Calculator (Members only)

Additional Help: Entering Your Recipe or Viewing Your Recipe Results.

The HSMG Lye Calculator is available for both members and non-members. In addition to all the basic functionality of a general lye calculator (specifying measurement units or percentage and calculating using sodium or postassium hydroxice, the HSMG Lye Calculator is unique in that you can see the actual Saponification Value (SAP Value) being used in the calculation.

About SAP Values

The Saponification Value (SAP Value) of an oil is typically determined as a standard range for any particular oil. The expected range is part of what standardizes the oil. If an oil has a SAP value outside of the standard range, it is considered unacceptable. Depending on the oil's source and the conditions in which it was produced, the SAP value will vary - but it should always be within the given range. The American Oil Chemists Society (AOCS) publishes the standardized SAP value range for most oils.

In the HSMG Lye Calculator, lye amounts are calculated based on the mid-range SAP value for an oil (averaged from the low and high ends of the SAP value range. In the Advanced Lye Calculator (members only), a different SAP value can be used to calculate the lye (useful if the oils has been tested and the exact SAP value for the oil is known).

Some manufactured butters and oils (such as "avocado butter," "coffee butter" or "aloe vera oil") are not listed by the AOCS as they are actually blended products created by combining ingredients, frequently including two or more oils. To accurately calculate the lye required to saponify such manufactured products you must have the amounts (or percentages) of the specific ingredients (which you should be able to get from the manufacturer) or get the actual SAP value of the product from the manufacturer. Without an accurate SAP value, the amount of lye necessary to saponify the oil cannot be calculated.

Advance Lye Calculator

An Advanced Lye Calculator is available to HSMG Members. It has several advanced features, including:

  • Exact SAP value for the particular oil can be entered (for example, if the oil batch has been tested and the SAP value for that particular batch is known)
  • Recipes using a combination of NaOH and KOH can be entered and calculated.
  • Recipe can be saved, and then accessed later to print or edit.

Disclaimer: The Handcrafted Soapmakers Guild, Inc. is providing this lye calculator to soapmakers free of charge. Every effort has been made to ensure that the SAP values used herein are accurate. However, even in the best case, the SAP values provided by reputable sources are only acceptable ranges for each oil. The actual SAP value being used in the calculations is the average of the highest and the lowest acceptable level for an oil and is generally considered the norm for calculating the lye necessary for soap. However, the actual SAP value of any batch of a particular oil may be somewhat higher or lower than the value used in the calculations here (even if it falls within the acceptable range). That all being said, the HSMG is not responsible for any injuries, losses or other damages that may result from using the information provided herein.