📖 How to Use This Conception Calculator
Select your calculation method (Due Date, Birth Date, or LMP), enter the date using day/month/year inputs, and get your estimated conception date, due date, LMP, and trimester information.
💑 How Conception Works
Conception is the moment when a sperm fertilizes an egg. For conception to occur, intercourse must happen during the fertile window - typically the 6 days leading up to ovulation. Sperm can survive up to 5 days, while the egg survives only 12-24 hours after ovulation.
📅 Calculation Methods
- Due Date Method: Conception = Due Date - 266 days (38 weeks)
- Birth Date Method: Conception = Birth Date - 266 days
- LMP Method: Conception = LMP + 14 days (standard ovulation day)
📊 Pregnancy Trimesters
- First (Weeks 1-12): Major organ development
- Second (Weeks 13-26): Baby grows, movement felt
- Third (Weeks 27-40): Baby gains weight, preparation for birth
💡 Understanding Your Fertile Window
- Ovulation occurs 14 days before your next period
- For 28-day cycle, ovulation around day 14
- Fertile window = 5 days before + day of ovulation
- Intercourse every 1-2 days maximizes chances
❓ FAQ
❓ How accurate is conception date calculation? ▼
Conception date estimates have ±3-5 days accuracy. Sperm can survive up to 5 days, and ovulation timing varies. Early ultrasounds (8-12 weeks) provide the most accurate dating.
❓ What if my cycle is longer than 28 days? ▼
For longer cycles, ovulation occurs later (e.g., 35-day cycle averages ovulation around day 21). This calculator assumes standard 28-day cycle. Track ovulation for more accuracy.
❓ Can I conceive after ovulation? ▼
No, the egg only survives 12-24 hours after ovulation. Once ovulation has passed, conception is not possible until the next cycle.
❓ How to calculate due date from conception? ▼
Due date = Conception date + 266 days (38 weeks). This is used when conception date is known through IVF or tracked ovulation.
❓ Why is LMP used instead of conception date? ▼
Most women don't know their exact conception date, but many track their menstrual periods. LMP provides a consistent starting point.
❓ Can I get pregnant right after my period? ▼
Yes, especially with short cycles. Sperm can survive up to 5 days. If you ovulate early (day 10-12), intercourse during your period could lead to pregnancy.