The Oil & Lye Soap Calculator is a great starting place for those who want to craft their own hard bar soap or liquid soap recipes. There is a ton of information provided on the recipe result page that is provided once the recipe is built and calculated. It does help to be knowledgeable on the basics of soap making, but over all it is made for all levels including the absolute beginner. This calculator may look familiar to some, and that is intentional. It was designed to be similar to an already popular calculator online but changed to make it easier to see and use. In keeping the steps in the same order, one need not go through the headache of learning something completely new, but the images were made larger, buttons were added to be more clear, and the advertisements that squished everything into a minuscule font were stripped away. Essentially, I recreated this for my own middle aged eyes so that I could see and understand it more easily. I have, however, left many of the values the same just so that it doesn't confuse or contradict the information to which people have grown accustom.

Learn How to Use the Calculator Below

What do all these numbers mean?


Reviewing the Hardness value.

This refers to the hardness of the soap bar.  Higher is harder.  The ideal range is around 29 to 54.

This number is a general guideline, and although a range is offered for a premium recipe there are other things to take into consideration when thinking about your finished project. The amount of super fat and the amount of water are going to contribute to the over all texture. Water of course, will eventually evaporate entirely, but a recipe with a high super fat will never saponify the extra oil and that floating oil will always remain soft no matter what.

This 'hardness' number comes by selecting out the saturated fatty acids and adding them together (lauric, myristic, palmitic, and stearic). In the image above you can see that Baobab Oil has a hardness rating of 29. The range we're shooting for is 29-54, so according to our calculator baobab oil falls on the soft side of the range. Baobab oil is really similar to coconut oil. Once it has fully cured it is just as hard as any soap and maybe even a little on the brittle side. More commonly olive oil is often used at 100% in a recipe, and its hardness value is below 20. Those who are familiar with making castile soap with 100% olive oil know that when the bar is fully cured it is a very hard bar of soap.

So what other information can we extract from this hardness value? Well, if you are familiar with my recipes, you'll know one of my favorite oils is palm and especially palm shortening. I love palm shortening for its long shelf life, and saturated fats are stand alone oils that last longer on the shelves than unsaturated fats. Since the hardness rating is a combination of all the saturated fats,the higher the hardness the longer the bars last.


Reviewing the Solubility value...

This is also labeled as the 'cleansing' value on some calculators. However, cleansing seems not quite right. To get this value the recipe adds together the lauric and mysteric acids. If you are building a bar of soap with the most common base oils this is going to compel you to always add coconut oil into every recipe. If you don't add coconut (or a few other) oils o the recipe this value tends to stay low. Of course, soaps made without coconut oil also cleans perfectly well. So, the description seems a little misleading even though it is correct. Let me explain......

The solubility value is a measurement of how much the soap will dissolve in water. Soap that dissolves really well also grabs oils as water carries it away. So, it some senses a soap that dissolves well grabs dirt and oil more aggressively as it passes over the skin. Intuitively one would think that the higher the 'cleansing' number the better the soap does its job. The problem with this idea is that the higher the number the more natural oil is stripped from the skin which can leave it feeling dry. So, keeping this to a modest range between 12 to 22 is an accepted goal in crafting an ideal recipe.

However, some recipe just come up much lower than 12 and it does not mean that the soap doesn't cleanse. It means that the soap is a little more rich in oil that will make a soap a little more gentle, which is why I prefer to use the term solubility.

Keep in mind, this number doesn't calculate any additives or superfats that you throw into the recipe. So, if you end up formulating a soap that leans toward a higher number the recipe can be affected over all with extra butters, fats, and waxes added afterward.


Reviewing the Conditioning value...

That smooth rich feeling left behind after use is referred to as the conditioning value. Anything left on the surface of the skin to keep moisture trapped or keep the skin smooth is going to contribute to the conditioning factor. To get this value the unsaturated fatty acids are added. These would be the light oils that contain oleic, linoleic, linolenic, and ricinoleic acid profiles.

Aiming for a goal in the mid range is ideal for the conditioning value.  A range of 44 to 69 is demonstrated in other calculators, so we have kept it this way as well. However, just like in the previous two examples this is a very general guide and different unsaturated oils can have a variation of results in the feel of the bar.

For example, olive oil has a conditioning factor of 82 and makes a beautiful bar of soap, but it is a soft and gentle bar and not known to be excessively conditioning. However, jojoba oil, which is actually a liquid wax, has a conditioning value of 12. Adding a layer of pure jojoba wax directly on the skin feels like soft velvet, and it might be said that the conditioning feel is very high. So there are exceptions to these general ranges, and the additives incorporated have to be taken into consideration. Super fats are also going to contribute to how soft and rich a bar of soap will feel and are not incorporate into this number.

So remember, as a general rule, most of your light weight seed and soy oils are going to balance a recipe by adding a soft conditioning feels to the bar. The soft light oils are not as stable as the heavier saturated fats and oils so keeping these proportions lower in your recipe will help the shelf life of your bar.


Reviewing the Bubbly Lather value...

This is probably the most obvious property in our soap formula. The bubble factor refers to a lather with individual bubbles. They can be large and fluffy or small and foaming, and the type of bubbles are influenced on the type of oils used in your recipe. The bubble value is created by adding three types of acids. The lauric and myristic are our main contenders, while the ricinoleic, which is usually castor oil, for a bubble stability. The range we are aiming for is somewhere between 12 and 50, with the higher number being bigger fluffier bubbles.

This refers to the soap’s ability to lather up and get bubbly.  A typical range of values would be 14 to 46. The higher Bubbly numbers will tend to produce a foamy, fluffy lather rather than a creamy lather with little or no bubbles.

When formulating a recipe there other additives that can contribute to the bubble scale.  Sugar in the form of milk, honey, or fruit puree can offer a boost in bubbles,which will not show up on the calculator.


Reviewing the value for Creaminess ......

Creaminess is also a form of bubble. A rich creamy lather will contain a tiny dense bubble that looks and feels silkier. The value in the creaminess scale represents how stable this type of lather is. Palm and steric acid are the two top contributors to the creaminess value. This range can be anywhere from 15 to 50 to get a stable creamy lather. One example of a soap that creates small dense bubbles is 100% palm soap. The creaminess score ranks at 49 and the result in a bar of palm soap is a creamy flow with bubbles that are almost to small to see without a magnifying glass. You can think of the creaminess scale and the bubble scale as opposites.  Typically,when you adjust the oils to boost one,the other will be decreased.

Wrapping It All Up

So, these are the categories that describe the properties of soap recipe using just the base oils as a result. Its important to remember that the numbers that you see will give you a mental snapshot of what kind of soap you are making with the base oils only. Additives will often alter these properties by boosting properties like bubbles and hardness. These numbers should be considered a generalization and some oils with be an exception in a few cases. The reason these numbers are relevant is because you can formulate the type of product you want to make based on the properties you need. For example, a shaving soap may want a creamy lather with almost no bubble, while a liquid shampoo may want big fat fluffy bubbles. This guide will help achieve the desired properties while keeping the formula balanced and pleasant.

 Of course, to get the perfect recipe for your desired type of soap there are many other things that come into play. You could also consider joining our community and engaging with over 3,000 soap making members. Everything from beginner courses and advanced recipes are packed into the pages in the Crafter's Community. Take a peek and learn more.....