This page is a crawler-accessible summary. The full interactive calculator is at https://makerstudio.livesoapschool.com/calculator.
How to Calculate a Soap Recipe
Enter your oils
Select the oils and butters in your recipe and enter the percentage or weight of each one. Use a preset recipe to start instantly.
Adjust your values
Set your batch size, lye type (NaOH for bar soap, KOH for liquid soap), superfat percentage, water ratio, and fragrance load.
Review your results
The calculator instantly shows your lye weight, water weight, fragrance amount, fatty acid profile, and quality scores. Print or save your recipe sheet.
What this calculator does
NaOH & KOH Lye Calculation
Calculates sodium hydroxide for bar soap and potassium hydroxide for liquid soap using accurate saponification values.
Water & Lye Concentration
Control your water-to-lye ratio and lye concentration percentage to dial in trace speed and bar hardness.
Superfat Adjustment
Set your superfat from 0–20%. The calculator adjusts lye weight automatically so your bar has exactly the conditioning level you want.
Fragrance Load
Enter your fragrance percentage and get the exact weight to add to your batch alongside lye and water.
Fatty Acid Profile
See the lauric, myristic, palmitic, stearic, oleic, linoleic, and ricinoleic acid breakdown of your complete formula.
Quality Score Prediction
Get predicted hardness, cleansing, conditioning, bubbly lather, creamy lather, iodine value, and INS score before you make a single batch.
Frequently asked questions
What is a soap calculator?
A soap calculator determines the exact amount of lye and water needed for a soap recipe based on the oils and butters you choose. It uses saponification values to calculate precise measurements so every batch is safe and consistent.
How do you calculate lye for soap?
Multiply the weight of each oil by its saponification value, sum the results, then reduce by your superfat percentage. A soap calculator automates this entirely — enter your oils, set your batch size, and the lye weight is calculated instantly.
What is superfat in soap making?
Superfat is the percentage of oils left unsaponified in your finished bar. Most cold process recipes use 5%. Higher superfat (8–10%) produces a more moisturizing bar; lower superfat (2–3%) produces a harder, longer-lasting bar.
What is the difference between NaOH and KOH soap?
NaOH (sodium hydroxide) produces solid bar soap. KOH (potassium hydroxide) produces liquid or soft soap. The saponification values differ between the two, so always select the correct lye type before calculating.
Is this soap calculator free?
Yes. The Maker Studio AI soap calculator is completely free with no account required. Creating a free account unlocks recipe saving, batch tracking, cost analysis, and the full ingredient intelligence suite.
Save your recipes. Track your batches. Grow your business.
The free calculator is just the start. Maker Studio AI connects your recipes to batch records, inventory, costs, and financials.
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