Saponification Value Calculator

Calculate saponification value (SV) of fats and oils in the laboratory. Enter titration data to determine the KOH required for saponification.

Sample weight in grams

Volume of KOH used in titration

Molarity of KOH solution

Titration volume for blank sample

Concentration of HCl for back-titration

Saponification Value Formula: SV = (V_blank - V_sample) × N × 56.1 / m Where: • V_blank = Blank titration volume (mL) • V_sample = Sample titration volume (mL) • N = Normality (M) of KOH • 56.1 = Molecular weight of KOH (g/mol) • m = Mass of sample (g) For soap making NaOH: NaOH needed = SV × 0.135 × fat mass (g) (0.135 accounts for NaOH vs KOH molecular weight)
Example 1 (Lab Determination): Sample mass: 2.0 g KOH concentration: 0.1 M Sample titration: 23.5 mL Blank titration: 25.0 mL KOH consumed: (25-23.5) × 0.1 = 0.15 mmol SV = 0.15 × 56.1 / 2.0 = 4.21 mg/g × 1000 = 204.2 Example 2 (Olive Oil): Calculated SV = 195 mg KOH/g For 500g olive oil: NaOH needed = 195 × 0.135 × 500 = 13,163 mg = 13.2 g Example 3 (Coconut Oil): Typical SV = 258 mg KOH/g For soap batch: 1 kg oil NaOH = 258 × 0.135 × 1000 = 34,830 mg = 34.8 g Example 4 (Average Molecular Weight): SV = 200 mg KOH/g MW_fat = (56.1 × 1000) / 200 = 280.5 g/mol

What is saponification value?

Saponification value (SV) measures the milligrams of KOH required to saponify 1 gram of fat or oil. It indicates the average molecular weight of fatty acids in the sample - lower SV means higher molecular weight (longer chain fatty acids), while higher SV means shorter chains.

How is saponification value determined?

The SV is determined by refluxing the fat with excess KOH solution, then back-titrating the unreacted KOH with HCl. The difference between blank and sample titrations gives KOH consumed. SV = (V_blank - V_sample) × N × 56.1 / mass, where N is normality of KOH.

What does saponification value indicate?

Saponification value indicates the chain length of fatty acids: SV ~280 = very short chains (capric acid), SV ~200-250 = medium chains (coconut, palm), SV ~180-200 = longer chains (olive, soy). It also indicates purity - adulterated oils will have different SV than pure oils.

What are typical saponification values?

Typical SV ranges: Coconut oil: 250-265, Palm oil: 190-210, Olive oil: 185-200, Castor oil: 175-187, Lard: 190-200, Butter: 220-240. These values help identify oils and determine appropriate NaOH amounts for soap making (NaOH KOH × 1.4 for equivalent weight).

Why is saponification important for soap making?

In soap making, knowing the saponification value lets you calculate exactly how much lye (NaOH) is needed to completely saponify a given amount of fat. Using too much lye creates a harsh soap; too little leaves excess unreacted fat. SAP value × 0.135 gives NaOH needed per gram of fat for sodium soap.

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