The operative interphase properties surrounding carbon nanotubes (CNTs) networks are applied to progress a simple and applicable simulation for the strength of nanocomposites. Both critical interfacial shear strength (τc) and interfacial shear strength (τ) define the operative depth and power of interphase area. The experimental results of selected examples and the parametric analyses are employed to accept the established model. The experimental data properly fit to the model's forecasts and all parameters reasonably affect the nanocomposite's strength. Very low τc (10 MPa) and extremely high τ (400 MPa) significantly improve the strength of nanocomposites by 700%, while τc > 43 MPa slightly increase the nanocomposite's strength. The strongest and the densest interphase around CNT nets can raise the strength of nanocomposites by 450%, but very poor or thin interphase only changes the nanocomposite's strength by 10%. Additionally, the narrowest and the biggest CNT produce the sturdiest samples, while thick CNT (CNT radius > 11 nm) cannot strengthen the polymer media.