What is a typical length of the average female menstrual cycle?

• A. 28 days
• B. 21 days
• C. 30 days
• D. 35 days

Answer: (A)

The length of a typical menstrual cycle is about 28 days, though normal cycles can range from roughly 21 to 35 days. The count starts on the first day of bleeding and ends the day before the next period begins. In a 28-day cycle, ovulation commonly occurs around day 14, because the luteal phase is usually about 14 days long and the variability mostly comes from the follicular phase. The other options fall outside the most commonly cited average: 21 days is on the shorter end, while 30–35 days are longer than the typical average, though they can occur. So 28 days best represents the standard average used in education and clinical references.