Menstrual Cycle & Fertile Window

Tracking menstrual cycle patterns helps women understand reproductive health, predict upcoming periods, and identify the fertile window for family planning or natural contraception awareness.

This calculator computes your estimated ovulation date (typically 14 days prior to the next expected period), the 6-day fertile conception window (5 days prior to ovulation plus ovulation day), and projects your next 6 menstrual cycles.

Next Period Date = Last Period Date + Cycle Length (days). Ovulation Date = Next Period Date - Luteal Phase Length (default 14 days). Fertile Window begins 5 days prior to ovulation and concludes 1 day after ovulation.