Cold Process Soap Lye Calculator
Enter the weight of each oil in your recipe to compute the exact NaOH (solid bar) or KOH (liquid) lye amount, water, and superfat ratio. Based on each oil's saponification value (SAP). Supports multi-oil blends of 20 common oils.
β Oil Recipe
β‘ Process Parameters
Results
| Oil | Weight (g) | Share | Lye (g) |
|---|
Reference: Saponification Values (NaOH)
Unit: grams of lye per 100 g of oil. Typical reference values β always confirm with your supplier's batch data.
| Oil | SAP | Oil | SAP |
|---|
Frequently Asked Questions
What is superfat?
Superfat keeps a portion of oil un-saponified, leaving the bar more moisturizing and adding a safety buffer against lye-heavy mistakes. Typical range is 3%β8%; above 10% the bar may be soft, oily, or prone to rancidity. This calculator reduces lye by the superfat percentage automatically.
What is the difference between NaOH and KOH?
NaOH (sodium hydroxide) makes solid bars; KOH (potassium hydroxide) makes liquid soap/shampoo. Their saponification values differ β KOH is about 1.403Γ NaOH, and the calculator converts automatically.
How much water should I use?
Commonly 30%β40% of oil weight. More water means slower trace and longer curing; less water means faster trace and shorter working time. Beginners should use 35%β40%.