Next Period Calculator
Adds homogeneous cycle spacing to LMP — irregular cycles reduce forecast usefulness.
Both fields are required.
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.