1. What is the Due Date Calculator?

The Pregnancy Due Date Calculator estimates the expected delivery date based on the first day of your last menstrual period (LMP), using the standard 280-day (40-week) pregnancy calculation method.

2. How Does the Calculator Work?

The calculator uses the Naegele's rule:

Where:

• LMP — First day of last menstrual period
• 280 days — Standard duration of pregnancy (40 weeks)

Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. The actual delivery date may vary by ±2 weeks.

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for prenatal care scheduling, monitoring fetal development, and determining if pregnancy continues past term.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period. For best accuracy, you should know your cycle length and ovulation date.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this due date calculation?
A: About 4% of women deliver on their due date. Most deliver within 2 weeks before or after.

Q2: What if my cycle isn't 28 days?
A: For cycles longer than 28 days, add the extra days to the due date. For shorter cycles, subtract the difference.

Q3: What if I don't know my LMP?
A: An early ultrasound (first trimester) can provide a more accurate due date estimate.

Q4: Why 280 days?
A: This is based on the average 40-week human gestation period from LMP (which includes about 2 weeks before conception).

Q5: What's the difference between gestational age and fetal age?
A: Gestational age counts from LMP (about 2 weeks older than fetal age, which counts from conception).