A frequency divider includes a first shifter and a second shifter. The first shifter includes first to M-th clock control components connected together to form a first ring. The control components in the first shifter are controlled by an input clock signal such that signals are shifted along the first ring. An output of selected clock control components in the first shifter is provided as a carry signal of the first shifter. The second shifter includes first to N-th clock control components connected together to form a second ring. The control components in the second shifter are controlled by the carry signal of the first shifter such that the signals are shifted along the second ring. An output of selected clock control components in the second shifter is provided as a carry signal of the second shifter. M and N are integers greater than one.