Pregnancy Conception Calculator
The Pregnancy Conception Calculator estimates the date of conception based on the expected due date of the pregnancy, last period date, or ultrasound date. The date of conception is the day on which a person’s baby is conceived. The calculator also estimates a possible range of days during which sexual intercourse might have led to conception based on sperm being viable for 3-5 days within a woman’s body.
Modify the values and click the calculate button to use
Calculate Based On:
Most probable conception date:
Jun 29, 2025
Most probable dates of sexual intercourse that led to the pregnancy:
Jun 24, 2025 to Jun 28, 2025
Possible conception dates:
Jun 15, 2025 to Jul 13, 2025
Possible dates of sexual intercourse that led to the pregnancy:
Jun 10, 2025 to Jul 13, 2025
The results of this calculator are estimation only.
When Did I Conceive?
Determining your exact conception date can be challenging, as pregnancy is typically calculated from the first day of your last menstrual period (LMP), even though conception usually occurs about 10-14 days after that. This calculator estimates your likely conception window and possible dates of intercourse that led to pregnancy.
How Conception Dates Are Estimated:
- Last Menstrual Period (LMP):
- Conception typically occurs 11-21 days after the first day of your last period.
- Less accurate for those with irregular cycles or uncertain LMP dates.
- Due Date:
- Based on your estimated due date (from a healthcare provider), conception is calculated by counting backward.
- Ultrasound:
- Provides the most accurate estimate, especially early in pregnancy (5-6 weeks after LMP).
- Measures fetal development to determine gestational age.
Understanding Fertilization vs. Conception:
- Fertilization: When sperm meets egg (occurs in the fallopian tube).
- Conception (Medical Definition): When the fertilized egg implants in the uterus—this is when pregnancy officially begins.
Since ovulation timing, sperm survival (3-5 days), and implantation can vary, this calculator provides a probable date range rather than an exact day. Results are estimates and should be confirmed with a healthcare provider.