Menstrual Period Calculator

Menstruation, or a period, is the process in which the lining of the uterus sheds and is discharged through the vagina. Typically, vaginal bleeding will last for 3 to 8 days.

A regular menstrual cycle lasts for about 25 to 35 days. The first day of your period marks the first day of your cycle. Cycles that are longer than 33 days or less than 25 may indicate hormonal problems. It is normal to have irregular cycles in the first 2 years after menarche (when a period first starts for an adolescent girl).