The hydrophilic–lipophilic balance (HLB) of a surfactant is a measure of its degree of hydrophilicityorlipophilicity, determined by calculating percentages of molecular weights for the hydrophilic and lipophilic portions of the surfactant molecule, as described by Griffin in 1949[1][2] and 1954.[3] Other methods have been suggested, notably in 1957 by Davies.[4]
Griffin's method for non-ionic surfactants as described in 1954 works as follows:
where 
The HLB value can be used to predict the surfactant properties of a molecule:
In 1957, Davies suggested a method based on calculating a value based on the chemical groups of the molecule. The advantage of this method is that it takes into account the effect of stronger and weaker hydrophilic groups. The method works as follows:[4]
where:
| Hydrophilic Groups | Group Number |
|---|---|
| -SO4−Na+ | 38.7 |
| -COO−K+ | 21.1 |
| -COO−Na+ | 19.1 |
| N (tertiary amine) | 9.4 |
| Ester (sorbitan ring) | 6.8 |
| Ester (free) | 2.4 |
| -COOH | 2.1 |
| Hydroxyl (free) | 1.9 |
| -O- | 1.3 |
| Hydroxyl (sorbitan ring) | 0.5 |
| Lipophilic Groups | Group Number |
|---|---|
| -CH- | -0.475 |
| -CH2- | -0.475 |
| CH3- | -0.475 |
| =CH- | -0.475 |