🌸 Ovulation & Fertility Calculator
Estimate your ovulation date and fertile window based on your last menstrual period and cycle length.
Your Cycle
Estimated Ovulation Date
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Fertile Window Start
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Fertile Window End
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Next Period (est.)
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Days Until Ovulation
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Understanding Your Fertile Window
Ovulation typically occurs 14 days before the next period (the luteal phase). An egg can be fertilized for only 12–24 hours after ovulation. However, sperm can survive 3–5 days in the reproductive tract, creating a fertile window of about 6 days.
Ovulation Day = LMP + (cycle length − luteal phase length)
Fertile Window = Ovulation Day − 5 to Ovulation Day + 1
Fertile Window = Ovulation Day − 5 to Ovulation Day + 1