Enter your oils and their percentages, and LyeLab App works out exactly how much lye and water to weigh out, for cold process or hot process soap.
Choose sodium hydroxide (NaOH) for hard bars or potassium hydroxide (KOH) for soft and liquid soaps. The calculator uses each oil's saponification value for the lye you pick.
Superfat is the share of oil left unsaponified, which makes a milder bar. Set any amount; 5% is a common starting point.
Set the water as a percentage of the oils, as a lye concentration, or as a water to lye ratio, whichever your recipe uses.
Hardness, cleansing, conditioning and lather are shown against their ideal ranges, so you can adjust the oils before you weigh anything.
Example: 70% olive oil and 30% coconut oil at 5% superfat and 33% lye concentration needs 142.3 g of sodium hydroxide and 288.9 g of water for 1000 g of oils.
Sodium and potassium hydroxide are caustic. Wear gloves and eye protection, add lye to water, never the reverse, and check every recipe before you make it.