Which is the longest phase of cell cycle?

Interphase is the longest phase of the cell cycle. More specifically, the G1 phase of interphase takes the most time to undergo its process. During G1, cells are highly metabolically active, and spend approximately 11 hours in this phase for typical proliferating human cells. In the G1 phase, cells experience most of their growth. They become larger in size, and make proteins and organelles necessary for DNA synthesis. RNAs and proteins are also synthesized in the G1 phase, and the centromere and other components of centrosomes are also created. The S phase takes approximately 8 hours, the G2 phase takes 4 hours, and the M phase lasts 1 hour. Thus, interphase in total makes up for 23 hours of the overall cell cycle.