1. What is the Pregnancy Due Date Calculator?

This calculator estimates the conception date based on the known due date of a pregnancy. It uses the standard 266-day gestation period from conception to birth.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• 266 days — Standard length of human gestation from conception
• Due Date — Estimated date of delivery (EDD)

Explanation: This calculation assumes a typical 38-week (266-day) pregnancy from conception to birth.

3. Importance of Conception Date Calculation

Details: Knowing the conception date helps in understanding the pregnancy timeline, estimating fetal development milestones, and can be useful for medical and personal records.

4. Using the Calculator

Tips: Enter the known due date in the format YYYY-MM-DD. The calculator will subtract 266 days to estimate when conception likely occurred.

5. Frequently Asked Questions (FAQ)

Q1: Why 266 days instead of 280 days (40 weeks)?
A: Pregnancy is typically counted as 40 weeks from the first day of the last menstrual period (LMP), but conception occurs about 2 weeks after LMP, making the actual gestation period 266 days (38 weeks) from conception.

Q2: How accurate is this calculation?
A: This provides an estimate. Actual gestation periods can vary naturally between 259-280 days from conception.

Q3: What if I know my ovulation date instead of conception date?
A: Conception typically occurs within 24 hours of ovulation, so the dates would be nearly identical.

Q4: Does this work for IVF pregnancies?
A: For IVF, the exact conception date is known, so this calculator isn't needed. The due date is calculated by adding 266 days to the embryo transfer date.

Q5: Why might my actual conception date differ?
A: Variations can occur due to natural differences in gestation length, uncertainty in due date estimation, or if ovulation/conception didn't occur exactly 14 days after LMP.