How long does the cell cycle take?

The duration of a cell cycle varies depending on the type of cell. Generally, simpler prokaryotic organisms have shorter cell cycles because they have smaller genomes and smaller amounts of DNA to be replicated. The more complex eukaryotic organisms have longer cell cycles. 

Human cells have a total cell cycle time of 24 hours. The cell cycle consists of 4 phases. Each of these phases has a different duration, adding up to a total of 24 hours. 

The longest is the G1 phase, which takes about 11 hours. The S phase is the second-longest, lasting about 7 hours. The G2 phase has a duration of 4 hours and the M phase, which is the shortest, lasts about 2 hours. 

Most of the differences in cell cycle duration between species and cells are found in the duration of specific cell cycle phases. Across species and organismal complexity, embryonic cells have an increased need for rapidity in the cell cycle because they need to multiply for the development of the embryo.