Interior melting degree Φ of our Earth and Mars analogues in steps of 1 (Earth) and 15 kyr (Mars) after first reaching the magma ocean liquidus after termination of accretion. Earth experiences rapid crystallization and a solidification that propagates first from the top of the magma ocean and down and later from the bottom up. A small region is left in the middle mantle with a melting degree that slowly approaches Φ = 0.4 below which the magma viscosity increases strongly. The Mars analogue crystallizes its magma ocean from the bottom up and more slowly, due to thermal blankering by its thick H₂-rich atmosphere that slows the cooling of the magma ocean.