Efficiency (Theoretical Plates):   N = 5.54 ( TR ) 2   W1/2   5.54 is a constant when using the "Half Height" method. TR is the retention time of the peak and W1/2 is the width at half height.

Capacity Factor (k'):   k' = tr — t0   t0 t0 = the volume of the mobile phase inside the column Flow Rate tr = Band Retention Time

Selectivity (Alpha Value):   a = k2 / k1

Peak Assymetry:   As = B/A (at 10% peak height) B = At 10% peak height, the width of a line from the slope to a perpendicular line drawn from the peak's height to the baseline @ 10% height. B is the tailing end of the chromatogram. A = At 10% peak height, the width of a line from the slope to a perpendicular line drawn from the peak's height to the baseline @ 10% height. A is the fronting part of the chromatogram.

Resolution:   Rs = (1/4)(a-1)(N)1/2[k/(1+k)] k = the average of two peaks.