It gives you the estimated starting dates for the next 12 periods. All you have to do is to enter the starting date of your last period and the average length of your period cycle. Period cycle is the length of time in days from the start of one period to the start of the next one. Normal menstruation can be anywhere between two and seven days with three to five days being most common. The normal range of blood loss is ten to eighty milliliters with thirty-five ml being the average. Human females experience menstruation from puberty till the start of menopause.
New Feature: This calculator enables you to export period dates to an external calendar such as: MS Outlook, Goolge Calendar, Yahoo Calendar and any other calendar that supports the MS Outlook Calendar CSV export format.
Instructions on how to import can be found by looking up the import function of the calendar you are using. Thanks to Seb for suggesting this feature. More
Flash File Source: Office on Women's Health, Department of Health and Human Services: womenshealth.gov