1. Pregnancy Weeks and Days Calculation

This calculator determines how many weeks and days pregnant you are based on your Last Menstrual Period (LMP) and the current date. This is the standard method used by healthcare providers to track pregnancy progress.

2. How the Calculation Works

The calculation uses these formulas:

Where:

• LMP — First day of your last menstrual period
• Current Date — Today's date or any date you want to check
• Weeks — Full weeks of pregnancy (integer)
• Days — Remaining days beyond full weeks (0-6)

Note: Pregnancy dating assumes a 28-day cycle with ovulation on day 14. Actual conception typically occurs about 2 weeks after LMP.

3. Importance of Tracking Pregnancy Duration

Details: Accurate pregnancy dating is essential for proper prenatal care, timing of tests, and determining the due date (approximately 40 weeks from LMP).

4. Using the Calculator

Instructions: Enter the first day of your last menstrual period and the current date (defaults to today). The calculator will display your pregnancy duration in weeks and days.

5. Frequently Asked Questions (FAQ)

Q1: What if I don't know my LMP?
A: An early ultrasound can estimate gestational age. Without LMP or ultrasound, dating is less accurate.

Q2: Why count from LMP instead of conception?
A: LMP is typically more reliably known than conception date, so it's the standard reference point.

Q3: What if my cycles aren't 28 days?
A: The calculator assumes 28-day cycles. For irregular cycles, consult your healthcare provider for adjustment.

Q4: How accurate is this calculation?
A: It's accurate for women with regular 28-day cycles. Ultrasound in first trimester provides most accurate dating.

Q5: When should I see a doctor?
A: Schedule prenatal care as soon as you know you're pregnant, typically around 8 weeks gestation.