Phenyl isomer distributions, within current commercial limits of HF and A1C13 linear alkylbenzene sulfonates (LAS), have little effect on dishwashing performance in light-duty liquids (LDL), detergency performance in heavy-duty powders (HDP), and interfacial tension value. The most important factor in determining performance differences among commercial LAS samples is carbon chain homolog distribution. Both HF and A1C13LAS perform equally well and can be used interchangeably in high-performance products. The optimum for foam stability in light-duty liquids shifts towards shorter alkyl chain length as water hardness increases. At 0 ppm water hardness the optimum occurs at C13: at 50–150 ppm the optimum moves to C11and C12; and above 150 ppm the optimum shifts to include C10, C11and C,12. The detergency performance optimum range in a phosphate built heavy-duty powder at 50 and 150 ppm water hardness includes the C12, C13and C14alkyl chain lengths. In a nonphosphate built powder the optimum is similar at 50 ppm hardness to that of a phosphate built powder, but shifts at 150 ppm hardness to include C11, C12and C1