Menstrual cycle starts with the first day of period and ends with the first day of the next period. Normal cycle for most women is between 28 and 32 days, but this can be shorter or longer.
Ovulation is a part of a normal menstrual cycle. During ovulation fertile egg is released into ovaries. Fertility period starts few days before ovulation and ends couple of days after. Ovulation calendar helps you plan you pregnancy and gives you insight into when is possible to have intercourse without the risk of pregnancy.