Kotex and MyMonthlyCycles offer free online menstrual period trackers. Each site features additional resources and tracking applications to help predict upcoming periods and keep records of past cycles.
Kotex offers two options on its period tracker website. The Quick Period Calculator estimates upcoming periods based on a brief questionnaire about the user's most recent period. Kotex's Personal Period Tracker keeps a detailed record linked to a registered account. This option requires more extensive details, such as the intensity of past menstrual symptoms on certain dates, to provide more accurate tracking.
MyMonthlyCycles allows users to create personal accounts to track their periods on the main website or the specialized mobile site. MyMonthlyCycles also features period reminder alerts and menstrual period charting, among other resources.