Soap
Soap Lye Calculator
Calculate NaOH or KOH, water and superfat from oil weights. Verify before use.
Open Calculator →Soap Making Calculators
The lye calculator uses typical published SAP values so you can plan a recipe. Independently verify before you mix. The cost calculator prices the batch.
Soap
Soap Cost Calculator
Price a soap batch and each bar from oils, lye, fragrance, labor and packaging.
Open Calculator →How soap lye and pricing work
Lye is oil weight times that oil’s SAP value, reduced by your superfat percentage. Water comes from the lye concentration you choose.
SAP values here are typical published averages. Supplier oils vary. Check a certificate of analysis or a second calculator before making soap.
Batch cost should include oils, lye, fragrance, color, packaging and the time to make, cut and cure.
FAQ
How does a lye calculator work?
It multiplies each oil weight by a saponification value, subtracts superfat, then calculates water from your lye solution concentration.
Can I use this lye calculator as the only check?
No. Treat it as a planning tool. Confirm the recipe with your oil data and a second trusted source before working with lye.