Calculation methodology

SoapCraft Pro calculations are deterministic: the same versioned inputs produce the same outputs. The engine keeps full precision through the dependency chain and rounds only for display or export.

Formulation chemistry

Oil percentages must total 100% and are converted to weights from an explicit target oil mass. Each oil's KOH-basis saponification factor is converted to a NaOH basis using the molecular-mass ratio. Superfat is applied once to the pure alkali demand. NaOH and KOH purity corrections are then applied independently so the result reports the actual as-supplied mass to weigh.

Mixed-alkali input is defined as KOH's share of pure alkali equivalents, not KOH's apparent share of the final gram weights. Water-to-lye ratio and lye concentration use total as-supplied alkali; water as percent of oils uses oil mass.

Data provenance

Production ingredient records require a stable identifier, KOH-basis value, source identifier, method, status, and reviewer state. Provisional or synthetic records may be used in tests but cannot authorize public chemistry. A public feature flag alone is not enough: selected ingredients must also be approved.

Sizing

Mold geometry provides volume, not a universal soap mass. Material density and headspace vary. Capacity results should use a maker's calibrated mold density where available and otherwise remain clearly labeled estimates.

Cost and price

Batch cost combines the costs supplied for ingredients, packaging, labor, overhead, waste, and yield. Markup and gross margin are different: markup compares profit to cost; gross margin compares profit to selling price. Missing cost bases must be shown rather than silently treated as complete.

Known boundaries

Calculator outputs do not infer skin performance, guarantee regulatory compliance, or determine IFRA fragrance limits without the exact supplier certificate. See the safety notice before using any chemistry output.