We propose a general formula for the melting temperature of metals in terms of electronic mass, electronic number, and nearest-neighbor lattice distance. We derive it from the instability of the transverse phonon in the solid phase, using the nearly free electron model. Including higher order terms of vibrations enhanced near the melting temperature, the electronic restoring force is reduced and the ionic one is negligible. This fact greatly brings down the melting temperature, bringing it close to experimental data in the range of 10% for Cs, Cu, Au, and Ba. Also, this theory confirms the Lindemann criterion.