The haploid number of chromosomes in humans is 23. Haploid refers to the number of chromosomes in a cell that contains only one set of chromosomes. In humans, the cells that are haploid are the sperm and egg cells.
Each human cell normally contains 46 chromosomes, which are arranged in 23 pairs. When a sperm cell fertilizes an egg cell, the resulting zygote (fertilized egg) contains 23 pairs of chromosomes, or a total of 46 chromosomes.
During the process of meiosis, which occurs in the cells that produce sperm and egg cells, the number of chromosomes is reduced from 46 to 23. This is because the cells divide twice, but the chromosomes only replicate once. As a result, each of the four resulting cells has only 23 chromosomes, which is the haploid number for humans.