1. What is the Conception Date Calculator?

This calculator estimates the conception date based on the due date by subtracting 266 days (38 weeks) from the due date. This is based on the typical 40-week pregnancy duration minus the standard 2 weeks before conception is possible.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• 266 days represents 38 weeks of gestation
• This accounts for the typical 40-week pregnancy duration minus the 2 weeks before ovulation/conception

3. Importance of Conception Date

Details: Knowing the conception date helps estimate fetal age, determine paternity windows, and understand fertility patterns. It's also useful for medical and legal purposes.

4. Using the Calculator

Tips: Enter the 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 specifically?
A: This accounts for 38 weeks of gestation from conception to due date, plus the typical 2 weeks between last menstrual period and conception.

Q2: How accurate is this calculation?
A: It provides an estimate. Actual conception may vary by ±5 days due to natural variation in ovulation timing and implantation.

Q3: Does this work for IVF pregnancies?
A: For IVF, the exact conception date is known, so this calculator isn't needed.

Q4: What if my pregnancy was longer or shorter than 40 weeks?
A: This is an average. Individual pregnancies may vary, especially if the due date was adjusted during prenatal care.

Q5: Can I use this for paternity determination?
A: It can estimate a conception window, but biological variability means paternity tests are more reliable for confirmation.