In order to figure out how to cook soap from scratch at home, you need to decide what properties you want to get from the coveted piece of soap. Whether it will be a body soap, or a shampoo soap, expect soft fine foam or large soap bubbles, you want to make a moisturizing soap, an antiseptic or a scrub soap. From all of this will depend on the composition of the soap and properties. In this article we will try step by step to figure out how to make a soap recipe.

Three whales of soap from scratch: alkali, oil and water

a92c65e523843e4ac9d3cdd2e46a9a5cRecall, in order to prepare soap from scratch, three components are enough: alkali, water, oil (fat). As alkali for solid types of soap, we use caustic soda NaOH, for liquid soap – caustic potassium KOH. Well, and in order to figure out how to choose oils for making soap from scratch, we recommend paying attention to our section Basic oils. In short,

  • palm kernel and coconut oil give a magnificent foam, olive oil, sweet almond oil and corn oil will create a stable foam
  • increase the hardness of the soap, and hence the time of washing – all the same coconut and palm kernel oil
  • moisturize – olive, shea butter, sweet almond oil and apricot kernel oil.

More about base oils and how to choose the right one for your skin type, read our article – How to choose base oil for your skin type.

Learning to make soap recipe from scratch

The method of making soap from scratch, the process of chemical (chemistry of soap), and therefore requires a serious approach and accurate calculation. Therefore, the exact weight of the oil is necessary, on which the weight of alkali and water will depend. Immediately by technology, choose those oils that you want to use in your soap and their amount. Next, you need to combine water and alkali, and for this you need to measure out these ingredients.

1.  How to measure alkali for making soap recipe from scratch:

The formula for calculating the amount of alkali:

Base oil mass * saponification number * 95% = required amount of NaOH.

If there are several oils in the composition, then to determine the weight of alkali, multiply the weight of each oil by the corresponding number of saponification, sum up all the works and multiply the result by 95%:

((Oil Weight1 × Saponification Number1) + (Oil Weight2 × Saponification Number2) + (Oil Weight3 × Saponification Number3)) × 95% = Caustic Soda Weight

Saponification number

Saponification is a chemical reaction, thanks to which soap is obtained from the mixture, and the alkali will completely dissolve in the oil. Of course, the saponification ratio for different oils varies.

Name of oil (fat) Saponification number (coefficient)
Jojoba oil 0,066-0,069
Grapeseed Oil Castor Oil Shea Butter 0,128
Wheat germ oil 0,132
Avocado oil 0,133
Linseed oil Olive oil Peach kernel oil

Sunflower oil

Apricot Kernel Oil Peanut Butter Pumpkin Seed Oil 0,135
Walnut Oil Sweet Almond Oil 0,136
Cocoa Butter Sesame Oil 0,137
Palm oil 0,141
Coconut oil 0,190
Rosehip oil 0,193
Milk fat 0,255
Beeswax 0,690

2.  How to measure water in soap from scratch

The formula for calculating water in soap from scratch

Oil weight, in grams × 0.375 = Water weight, in grams

When using multiple oils:

The sum of the weight of all oils, in grams × 0.375 = Weight of water, in grams

3. An example of calculating the amount of caustic soda and water in soap from scratch

(The total composition of 1 kg of oil)

Butter Weight, g Saponification coefficient (number)
Olive 500 0,134
Palm 400 0,141
Shipovik 100 0,193

Substitute the data in the formula for calculating caustic soda:

((500×0,134) + (400×0,141) + (100×0,193)) × 95 % = 142,7×0,95 = 135,6 (g) – the weight of caustic soda per 1 kg of oil.

Substitute the data in the formula for calculating water:

(500 + 400 + 100) × 0,375 = 375 (g) – water weight per 1 kg of oil.

Soap your own hands on the table

The resulting recipe:

Olive oil – 500 g

Palm oil – 400 g

Rosehip oil – 100 g

Alkali (caustic soda) – 135.6 g

Water (ice) – 375 g

This is a good example of how a hand-held soap calculator works.

Soap calculator

Creating your own recipe for soap from scratch, you can use existing calculators, where it is enough to specify the desired oils and their weight, and the computer will calculate the necessary amount of alkali and water. That is, in principle, you do not need to know the number of saponification, this coefficient is automatically embedded in the calculator. Examples of several calculators from the Internet:,, Http: // It also indicates how much your recipe is balanced, it is often better to pay special attention to this parameter.

If you trust only your own calculations, then use the above formulas and coefficients.