How to Know How Many Days You Have in Your Menstrual Cycle

According to the National Women's Health Information Center, the average menstrual cycle length is 28 days, but cycles can range from 21 to 35 days in adults and 21 to 45 days in teens. Hormone levels in the body control the menstrual cycle. Women trying to get pregnant or those avoiding pregnancy may need to determine the length of their menstrual cycle. Abnormally long or short menstrual cycles can signify a problem that needs to be evaluated by a gynecologist, and proper calculation of your menstrual cycle can ensure that you give your physician correct information.

Instructions

• 1

  Determine the first day of bleeding with your menstrual period. This counts as cycle day one.

• 2

  Count and mark with a pen or pencil each day on a calendar until your second menstrual period begins.

• 3

  Calculate the number of days between cycle day one and the day before the start of your second period. This number of days is the length of your menstrual cycle.