Saponification Value Calculator
A high value means SHORT chains — more small molecules per gram, each bringing three ester bonds.
The formula
SV = 3 * 56105 / molar mass of the triglyceride
Milligrams of potash per gram of fat
The saponification value is how much potassium hydroxide it takes to hydrolyse a gram of fat completely. A triglyceride carries three ester bonds, so it consumes three moles of alkali per mole of fat, and the 56,105 in the formula is simply the molar mass of KOH in milligrams.
It measures chain length, backwards
A high saponification value means a LOW molar mass, because more small molecules fit into a gram and each brings three ester bonds with it. Coconut oil, rich in short and medium chains, runs around 255; rapeseed oil with its long chains sits near 175. The number is a chain-length measurement wearing a titration's clothing.
Soapmakers use the sodium version
Divide by 1.403 to convert to sodium hydroxide, which is lighter per mole and gives a hard bar rather than a soft or liquid soap. Recipes are usually run at a slight alkali deficit — a superfat of five per cent or so — so that no unreacted lye survives into the finished bar.
Where these models stop
Michaelis-Menten assumes a single substrate and a steady state; Langmuir assumes one layer on identical sites with no interaction between them; Stokes-Einstein assumes a hard sphere much larger than the solvent molecules around it. Each is an idealisation that happens to describe real systems well over a useful range, and each fails predictably outside it. Knowing which assumption a number rests on is usually more valuable than the number.