1. What Is Pregnancy Weeks Calculator?

The Pregnancy Weeks Calculator determines how many weeks pregnant you are based on your last menstrual period (LMP) date. This is the standard method used by healthcare providers to estimate gestational age.

2. How Does The Calculator Work?

The calculator uses the following formula:

Where:

• \( LMP \) — Last Menstrual Period date
• \( Current\ Date \) — Today's date or any specified date
• \( \lfloor \rfloor \) — Floor function (rounding down to nearest whole number)

Explanation: The calculation counts the number of days between your LMP and current date, then divides by 7 to get the number of weeks, rounding down to the nearest whole week.

3. Importance Of Pregnancy Dating

Details: Accurate pregnancy dating is crucial for monitoring fetal development, scheduling prenatal tests, determining due date, and making important healthcare decisions throughout pregnancy.

4. Using The Calculator

Tips: Enter your last menstrual period date and the current date (defaults to today). Ensure dates are accurate for precise calculation. The result shows complete weeks of pregnancy.

5. Frequently Asked Questions (FAQ)

Q1: Why is pregnancy calculated from LMP instead of conception?
A: LMP is used because it's easier to pinpoint than conception date. Pregnancy is typically 40 weeks from LMP, which includes about 2 weeks before actual conception.

Q2: What if I don't know my exact LMP date?
A: If unsure, use your best estimate. An ultrasound in early pregnancy can provide more accurate dating if LMP is uncertain.

Q3: How accurate is this calculation?
A: Very accurate for women with regular 28-day cycles. Variations may occur with irregular cycles or uncertain LMP dates.

Q4: When should I see a healthcare provider?
A: Schedule your first prenatal appointment around 8 weeks of pregnancy, or sooner if you have medical concerns or risk factors.

Q5: What are the pregnancy trimesters?
A: First trimester: weeks 1-13, Second trimester: weeks 14-27, Third trimester: weeks 28-40+.