How long is a Typical Menstruation Cycle?

The typical menstrual cycle is 28 days long, but each woman is different.2 Also, a woman’s menstrual cycle length might be different from month-to-month. Your periods are still “regular” if they usually come every 24 to 38 days.3 This means that the time from the first day of your last period up to the start of your next period is at least 24 days but not more than 38 days.
Some women’s periods are so regular that they can predict the day and time that their periods will start. Other women are regular but can only predict the start of their period within a few days.