Polarity, partition coefficient (K), methanol carbon number of surfactant ((C_(MeOH))_S), and methanol carbon number of surfactant head group ((C_(MeOH))_(HG)) are measured on six alkanolamides and five polyoxyethylenated long chain amines as stationary phases. From the measured methanol carbon numbers, polarity indices, (IP)_S and (IP)_(HG), are calculated. The determined polarity terms are plotted against the head group weight fraction ( f_(HG) ) of the investigated surfactants and several equations have been developed. The study reveals that the molecular structural gap between alkanolamides and polyoxyethylenated long chain amines diminished when HLB numbers of these surfactant classes are plotted against f_(HG) values. Consequently, a general equation relating HLB and f_(HG) is obtained. Polarity, partition coefficient (K), methanol carbon number of surfactant ((MeOH) _ S), and methanol carbon number of surfactant head group ((C_ (MeOH)) _ (HG) are measured on six alkanolamides and five From the measured methanol carbon numbers, the polarity indices, (IP) _S and (IP) _ (HG), are calculated. The determined polarity terms are plotted against the head group weight fraction (f_ (HG ) of the investigated surfactants and several equations have been developed. The study reveals that the molecular structural gap between alkanolamides and polyoxyethylenated long chain amines diminished when HLB numbers of these surfactant classes are plotted against f_ (HG) values. relating HLB and f_ (HG) is obtained.