Conception Calculator
Calculate conception date based on due date or last menstrual period
Calculate Conception From
Date Information
Additional Information
days
weeks
Your Conception Results
Based on your provided information
January 1, 2024
Estimated Due Date: October 8, 2024
Week 12 of 40
Based on Due Date
Pregnancy Timeline
Estimated Fertility Window
Based on your conception date, here is your estimated fertility window:
| Event | Date | Description | Fertility Level |
|---|
About Conception Calculation
Conception occurs when a sperm fertilizes an egg, typically around the time of ovulation. Pregnancy dating begins from the first day of your last menstrual period (LMP), which is about 2 weeks before conception actually occurs.
Calculation Methods
| Method | Calculation | Description | Accuracy |
|---|---|---|---|
| Due Date to Conception | Due Date - 266 days | Calculates conception date from estimated due date | Good estimate if due date is accurate |
| LMP to Conception | LMP + 14 days | Calculates conception from last menstrual period | Standard medical calculation |
| Current Date to Conception | Current Date - (Weeks × 7) + 14 days | Calculates conception if you know current pregnancy week | Good estimate if pregnancy week is known |
Conception and Pregnancy Timeline
| Time Frame | Event | Description | Development |
|---|---|---|---|
| Day 1-14 | Pre-conception | Follicular phase, egg development | Egg matures in ovary |
| Day 14 | Ovulation & Conception | Egg released and fertilized | Conception occurs |
| Day 15-21 | Early Development | Cell division, implantation | Blastocyst forms and implants |
| Week 4-5 | Pregnancy Detection | Missed period, positive test | Embryonic development begins |
| Week 6-8 | Heartbeat | First ultrasound, heartbeat detected | Major organs begin forming |
Understanding Conception
- Conception Date: The actual date when sperm fertilizes the egg (usually within 24 hours of ovulation)
- Gestational Age: Calculated from the first day of your last menstrual period (LMP), about 2 weeks before conception
- Fertile Window: The 5-6 days leading up to and including ovulation when conception is possible
- Implantation: Occurs 6-12 days after conception when the embryo attaches to the uterine wall
- Pregnancy Test: Can typically detect pregnancy 10-14 days after conception
Important Notes
- These calculations provide estimates - actual conception dates may vary
- Only about 5% of babies are born on their exact due date
- Sperm can live inside the female body for up to 5 days
- An egg is viable for about 12-24 hours after ovulation
- Ultrasound dating in early pregnancy is the most accurate method
- Always consult with your healthcare provider for accurate dating