Title: hydrophile-lipophile balance system
Long Title: IUPAC Gold Book - hydrophile-lipophile balance system
DOI: 10.1351/goldbook.15196
Status: current

Definition
Empirical scale (of \(0\!-\!20\)) used to classify surfactants and emulsifying agents.

Notes
1) The numerical value is determined by the expression (\({\rm{HLB}} = 20 M_{\rm{h}}/M\)) where \(M_{\rm{h}}\) is the molecular mass of the hydrophilic portion of the molecule, and \(M\) is the molecular mass of the whole molecule, giving a result on an arbitrary scale of \(0\!-\!20\).
2) An HLB value of \(0\) corresponds to a completely hydrophobic molecule, while a value of \(20\) corresponds to a molecule made up completely of hydrophilic components.
3) The more hydrophilic the surfactant the more it favors the formation of o/w over w/o emulsions.

Example
Ionic surfactants such as sodium lauryl sulfate have, e.g., an HLB of \(40\).

Source
- PAC, 2009, 81, 971. 'Glossary of terms related to pharmaceutics (IUPAC Recommendations 2009)' on page 987 (https://doi.org/10.1351/PAC-REC-04-10-14)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/15196/html
- json: https://goldbook.iupac.org/terms/view/15196/json
- xml: https://goldbook.iupac.org/terms/view/15196/xml

Citation: Citation: 'hydrophile-lipophile balance system' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15196
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Accessed: 2026-06-28T15:48:13+00:00