At what stage of mitosis would dna double?

Interphase (although not considered part of mitosis) is the phase in which DNA doubles. Interphase is basically the time in between period of growth between mitosis occurrences. Interphase can be broken up into three time periods: G1 phase (cell growth), S phase (DNA replication), and G2 phase (preparation for mitosis). Then after all of interphase has been completed, the cell starts mitosis with prophase.