Oleic acid: SAP value and fatty acids
Oleic acid has a saponification value of 199.5 mg KOH/g. One gram needs 0.142 g of sodium hydroxide (NaOH) for bar soap or 0.200 g of potassium hydroxide (KOH) for liquid soap to turn fully into soap, before any superfat.
Key numbers
- SAP, NaOH
- 0.14222 g per g oil
- SAP, KOH
- 0.1995 g per g oil
- Saponification value
- 199.5 mg KOH/g
- INCI name
- Oleic Acid
Example: 100 g of Oleic acid with no superfat needs 14.2 g of 100% NaOH, or 20.0 g of 100% KOH. A 5% superfat uses 5% less.
In soap
We don't have a sourced fatty-acid profile for it yet, so Soap Ledger shows no soap-quality scores for recipes that use it. The lye calculation still works.
A free fatty acid (liquid), not a fat; it neutralises lye directly and adds no glycerin. Pure oleic acid needs 198.6 mg KOH/g.
Sources
SAP value: 199.5 mg KOH/g (JSQI 2021 acid-value range midpoint (pure free acid: SAP = acid value)), from Theoretical SAP of pure lauric acid from molar mass, computed (56106 / molar mass). Printed value: 56106 / 282.46 (C18H34O2) = 198.6 mg KOH/g.
Published values we checked:
- acid value 195～204 mg KOH/g — Ministry of Health, Labour and Welfare (Japan)
- 56106 / 282.46 (C18H34O2) = 198.6 mg KOH/g — computed (56106 / molar mass)
NaOH and KOH values are converted from mg KOH/g with the molar masses 39.997 and 56.106 and rounded to 6 decimals, exactly as in the Soap Ledger app. Real oils vary by origin, grade and lot: check your supplier's certificate of analysis. Verify every weight before you make this, and follow lye safety. Not a safety or compliance certification.
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