💗 Pregnancy Tool
Conception Calculator
Curious about when your baby was conceived? Use your due date, last period, or ultrasound date to calculate your estimated conception date and fertile window.
Calculate Conception Date
Estimated Conception Date
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Possible Intercourse Dates
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Due Date
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How is Conception Calculated?
Conception usually occurs within 12 to 24 hours after ovulation. Because sperm can live inside the female reproductive tract for up to 5 days, intercourse leading to conception can happen several days before the actual conception date.
This calculator subtracts exactly 266 days (38 weeks) from your estimated due date to find your conception date. It then highlights the 5-day window leading up to that date as the most likely time intercourse occurred.