Conception Calculator
Reverse calculate your likely conception date from a due date or birth date.
Estimated Conception Date
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Conception Window
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Estimated LMP
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Gestational Age at Birth
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How to Use the Conception Calculator
- Choose your method: Select whether you know the due date or the birth date.
- Enter the date: Provide the due date or the actual birth date.
- View results: See the estimated conception date and conception window.
How Conception Date is Estimated
Conception typically occurs about 266 days (38 weeks) before the due date or birth date. Since conception can happen within a window of several days around ovulation, we provide a 5-day conception window.
Frequently Asked Questions
How accurate is a conception date estimate?
Conception date estimates are approximate. Sperm can survive up to 5 days, and the exact timing of ovulation varies. The actual conception could have occurred within a window of several days.
Can I determine the exact day of conception?
It is generally not possible to determine the exact day of conception without medical testing. This calculator provides a reasonable estimate based on standard gestational timing.