Health & Body Suite
Menstrual Period Calculator
Track cycle dates, estimate your next periods, predict ovulation, and find your most fertile windows to plan ahead with confidence.
1. Cycle Parameters
2. Projected Milestones
Calculated Next Period Starts Predicted
June 29, 2026 Est. Due Date (If Conception Occurs) March 22, 2027
📅 Menstrual Biology & Cycle Tracking Science
Tracking your menstrual cycle provides vital insights into your endocrine health and overall biological rhythms. The cycle is divided into distinct phases, each regulated by fluctuating hormone levels.
Phases of the Menstrual Cycle
- Menstrual Phase: The cycle starts with menstruation (bleeding), which represents the shedding of the uterine lining (endometrium). Lasts typically 3–7 days.
- Follicular Phase: Starts on day one of your period and lasts until ovulation. Estrogen levels rise as follicles in the ovaries mature, preparing to release an egg.
- Ovulation: The release of a mature egg from the ovary. This happens approximately 14 days before the next period starts. The egg lives for 12–24 hours after release.
- Luteal Phase: The time between ovulation and your next period. Progesterone rises to thicken the uterine lining in preparation for potential pregnancy. If fertilization does not occur, hormone levels drop, triggering menstruation.
Estimating Your Fertile Window
A woman's fertile window is the timeframe in which pregnancy is biologically possible. This window spans a total of 6 days: the day of ovulation and the 5 days prior. This is because sperm can remain viable in the reproductive tract for up to 5 days, waiting to fertilize the egg upon release.