Home
Back
Conception Date Formula:
| From: | To: |
Conception date calculation estimates when fertilization likely occurred based on the last menstrual period (LMP). It helps determine gestational age and expected due date in pregnancy.
The calculator uses the standard medical formula:
Where:
Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring approximately 14 days after the start of the last menstrual period.
Details: Knowing the conception date is crucial for accurate pregnancy dating, determining gestational age, calculating expected due date, and monitoring fetal development milestones.
Tips: Enter the first day of your last menstrual period in the date field. The calculator will automatically estimate your likely conception date by adding 14 days to your LMP.
Q1: How accurate is this calculation?
A: This provides an estimate based on average cycles. Actual conception may vary by a few days depending on individual cycle length and ovulation timing.
Q2: What if my menstrual cycle isn't 28 days?
A: For cycles longer or shorter than 28 days, adjustment may be needed. Ovulation typically occurs about 14 days before the next period starts.
Q3: Can conception occur outside the estimated date?
A: Yes, sperm can survive up to 5 days in the female reproductive tract, so conception could occur from intercourse 1-5 days before ovulation.
Q4: How is this different from due date calculation?
A: Due date is typically calculated as LMP + 280 days (40 weeks), while conception date is LMP + 14 days (assuming conception at 2 weeks gestation).
Q5: When should I confirm with ultrasound?
A: Early pregnancy ultrasound (6-9 weeks) can provide more accurate dating, especially if LMP is uncertain or cycles are irregular.