Calculator / NaOH cold process

Turn a good idea into a clear formula.

Build a bar from source-linked SAP values. This first release supports NaOH cold-process bars only.

Always wear proper safety gear.

Source-linked, not yet administrator reviewed. Reference SAP values still need administrator review. Check the linked sources and independently verify the formula before handling sodium hydroxide (NaOH, commonly called lye).

Step 01

Choose your ingredients

Enter the weight of each oil in grams or ounces. Their sum determines the formula size, NaOH, and liquid.

Enter oil amounts inEnter weights first; then you can adjust percentages against that total.

IngredientWeight (g)

Choose an ingredient above to begin.

Total oils · 0.0%0.0 g · 0.00 oz

Step 02

Choose your mixing liquid

Superfat5%

0%15%

Liquid for NaOH solution

Automatic starting estimate: Liquid is approximately 22% of the complete batch before saponification (oils + NaOH + fragrance + liquid), not 22% of oils alone. Oil SAP values and superfat determine the NaOH amount, assuming 100% sodium hydroxide purity. Fragrance adds to batch weight and changes this liquid estimate slightly, but never the NaOH amount. This is our approximation of a typical liquid share, not a verified supplier formula or a recipe-specific optimum. Check the supplier’s sodium hydroxide purity and follow a tested recipe.

Safety first. Slowly add NaOH to the measured liquid, never liquid to NaOH. Wear eye protection, gloves, and long sleeves, and work with ventilation. Milk mixtures need careful temperature control.

Step 03 / optional

Add your fragrance

Choose a fragrance from the menu. Its calculated amount follows your oil units (g); when oil percentages are selected, fragrance amounts use grams.

Are you adding fragrance to this batch?

You can leave it unscented, or choose a fragrance and let the calculator set the amount.

Total fragrance0.00 g

Check before making. The six documented entries use product-linked IFRA 51 statements assessed in September 2026; verify the supplier’s current statement for your exact product and batch. For other products, enter the matching soap-specific maximum yourself; without it, the automatic dose stays at zero. Our conservative screen uses oil weight because cured soap weight is not known. Blends need separate supplier review. Fragrance changes liquid, never NaOH.

Step 04

Check your formula

Validate oil percentages, NaOH calculations, and fragrance amounts before printing or saving. Supplier IFRA rates are screened only when you select a documented product or enter a matching rate; missing limits hold automatic fragrance amounts at zero.