In the thermodynamic framework of coupled statistical associating fluid theory variable range (SAFT-VR) 2D and 3D models we present the theoretical predictions of the adsorption isotherms in real physical units, as it is commonly done in experiments. The systems studied are methane (CH4), nitrogen (N-2), ethane (C2H6), n-butane (C4H10), propane (C3H8), and propylene (C3H6) adsorbed on silica gel (two classes: NSG and WSG), zeolite (4A and Na-Y), and BDH activated carbon. Employing only two fitting parameters with clear physical meaning in such an approach, we find a better agreement with the experimental data than other semiempirical models with more fitting parameters.