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Explore an estimated ovulation date alongside a clearly labelled uncertainty interval.
Adults tracking natural menstrual cycles. Calendar models describe timing rather than fertility status.
Model ovulation = next estimated period − 14 days. A broader ovulation interval uses 10–16 days before that period. Each fertility interval extends five days before through one day after its ovulation estimate. These are illustrative calendar intervals, not probability estimates or exhaustive pregnancy-risk bounds; pregnancy can occur outside highlights. The calendar marks period starts without inventing a bleeding duration.
Enter your dates to explore your estimated cycle calendar.
Calculate to see your dates on a calendar, with clearly marked estimates and cycle details.
Calendar estimates cannot confirm ovulation or identify pregnancy-safe days. Changing your inputs clears the previous calendar.
