Menstrual Cycle Calculator
Harmonizes last period baseline and averaged cycle spacing to summarize approximate next period onset, fertile midpoint, and luteal tail — calendar math only.
Enter dates to summarize.
Important usage notes & limitations
Reproductive timelines interact with contraception cessation, PCOS phenotype, transgender hormone therapy intensity, low body-fat athletic amenorrhea, and perimenopause. Hormonal contraception intentionally suppresses natural ovulatory signals until washout stabilization — calendar methods become meaningful only once cycles resume reliably.
See also: Pregnancy Due Date Calculator · Women's health calculators hub.