The Phase Inversion Temperature of a reference C 10 E 4 /n-Octane/Water system exhibits a quasi-linear variation versus the mole fraction of a second surfactant S 2 added in the mixture. This variation was recently proposed as a classification tool to quantify the Hydrophilic–Lipophilic Balance (HLB) of commercial surfactants. The feasibility of the so-called PIT-slope method for a wide range of well-defined non-ionic and ionic surfactants is investigated. The comparison of various surfactants having the same dodecyl chain tail allows to rank the polar head hydrophilicity as: SO 3 Na⩾SO 4 Na⩾NMe 3 Br>E 2 SO 3 Na≈CO 2 Na⩾E 1 SO 3 Na⩾PhSO 3 Na>Isosorbide exo SO 4 Na≫Isosorbide endo SO 4 Na≫E 8 ⩾NMe 2 O>E 7 >E 6 ⩾Glucosyl>E 5 ⩾Diglyceryl⩾E 4 >E 3 >E 2 ≈Isosorbide exo >Glyceryl>Isosorbide endo . The influence on the surfactant HLB of other structural parameters, i.e. hydrophobic chain length, unsaturation, replacement of Na + by K + counterion, and isomerism is also investigated. Finally, the method is successfully used to predict the optimal formulation of a new bio-based surfactant, 1-O-dodecyldiglycerol, when performing an oil scan at 25°C.