Learn the difference between NaOH and KOH in soap making, how each type of lye works, what soaps they create, and how to safely calculate recipes for handmade soap.
What Is the Difference Between NaOH and KOH in Soap Making?
One of the first things new soap makers discover is that there are two common types of lye used in soap making: NaOH and KOH.
While both are alkaline substances used for saponification, they create very different types of soap and behave differently during formulation.
Understanding how sodium hydroxide and potassium hydroxide work will help you create safer, better, and more consistent soap recipes.
What Is NaOH?
NaOH stands for Sodium Hydroxide.
In soap making, NaOH is commonly called:
- Caustic Soda
- Soap Lye
- Sodium Lye
Sodium hydroxide is used primarily for creating:
- Cold process bar soap
- Hot process soap
- Solid soap bars
- Soap loaves
What Is KOH?
KOH stands for Potassium Hydroxide.
In soap making, KOH is mainly used for:
- Liquid soap
- Soft soap paste
- Foaming soap products
- Dilutable liquid soap concentrates
Potassium hydroxide creates a softer and more water-soluble soap compared to sodium hydroxide.
That is why liquid soaps are normally made with KOH instead of NaOH.
Main Difference Between NaOH and KOH
| Feature | NaOH | KOH |
|---|---|---|
| Full Name | Sodium Hydroxide | Potassium Hydroxide |
| Main Soap Type | Solid Bar Soap | Liquid Soap |
| Soap Texture | Hard | Soft / Liquid |
| Water Solubility | Lower | Higher |
| Typical Use | Cold Process Soap | Liquid Soap Making |
| Soap Cure | Requires curing | Usually diluted into liquid soap |
Can You Mix NaOH and KOH?
Yes.
Some advanced soap makers combine sodium hydroxide and potassium hydroxide in hybrid recipes to create:
- Cream soap
- Shaving soap
- Semi-soft soap textures
- Custom lather profiles
However, beginner soap makers should usually work with one lye type at a time until they fully understand recipe calculations.
Why Accurate Lye Calculations Matter
Both NaOH and KOH are highly alkaline chemicals and must be measured accurately.
Incorrect lye calculations can cause:
- Harsh soap
- Skin irritation
- Unsafe soap bars
- Soft or failed batches
- Separated liquid soap
This is why reliable soap calculators are essential for safe soap making.
A Good Soap Calculator Should Handle
- NaOH recipes
- KOH recipes
- Superfat percentages
- Oil SAP values
- Water calculations
- Recipe scaling
- Soap quality analysis
- Fragrance calculations
Safety Tips for Handling Lye
Whether using sodium hydroxide or potassium hydroxide, safety should always come first.
- Always wear gloves and eye protection
- Mix lye in a ventilated area
- Always add lye to water — never water to lye
- Keep lye away from children and pets
- Use accurate digital scales
- Store lye in sealed containers
Using the BulkWork Suite Soap Calculator
The BulkWork Suite free soap calculator supports both NaOH and KOH calculations and helps soap makers build balanced recipes faster.
You can:
- Switch between NaOH and KOH instantly
- Calculate precise lye amounts
- Adjust superfat levels
- Track fragrance and additives
- Analyze soap quality values
- Print recipe sheets
Try the Free Soap Calculator
Calculate NaOH and KOH soap recipes with the BulkWork Suite free soap calculator.
Launch Free Soap Calculator
