The existing “quotidian equation state” model, based on Thomas-Fermi theory, is modified so as to improve the low density region of phase diagram of metals. A scheme for estimating the critical parameters of liquid-vapor phase transition is proposed. The new model reproduces experimental critical isotherms to a good degree of accuracy. Furthermore, the proposed model is validated with thermodynamic data in the liquid-vapor co-existence region, including results on isobaric expansion as well as released isentropes.