Volume-explicit equations of states for hard chains, their mixtures, and copolymers were developed. The equations accurately represent the simulation data. They also predict the correct volume at high pressures (close packing), unlike the common pressure-explicit equations, which predict a physically unattainable volume. Entropic demixing is also predicted by the proposed equations. The developed equation can be used as the repulsive part in developing volume-explicit real polymer equations of stare or excess Gibbs energy models.