To calculate menstrual cycle length you count the number of days from day one of your period CD 1 up to and including the day before the next period starts. An average menstrual cycle is 28 days long but some. The menstrual cycle is.
You could also use apps for menstrual cycles.
Count forward however many days your menstrual cycle normally is before you start. The Menstrual Cycle Length Calculator is used to calculate your menstrual cycle length based on the first day of your last two menstrual period. It is a cycle that usually begins between 12 and 15 years of age that continues up until menopause which on average occurs at the age of 52. If your cycle lasts up to 28 days your ovulation will be around day 14 two weeks before your next period.