Pregnancy Calculator

How Pregnancy Dating Works

Pregnancy is calculated from your last menstrual period (LMP), not conception. This adds 280 days (40 weeks) from your period start date, making you "2 weeks pregnant" before you even conceive!

The Three Calculation Methods

• Last Menstrual Period: Most common, adds 280 days
• Conception Date: If known, adds 266 days
• Due Date: Working backwards from doctor's date
• Ultrasound Dating: Most accurate in first trimester

Key Pregnancy Milestones

• Week 12: End of first trimester, reduced miscarriage risk
• Week 20: Anatomy scan, gender determination
• Week 24: Viability milestone
• Week 37: Full-term pregnancy begins

What to Expect Each Trimester

Pregnancy unfolds in three distinct phases, each with unique developments and symptoms. Here's what typically happens in each stage.

First Trimester (0-12 weeks)

• Baby: Major organs form, heart starts beating
• You: Morning sickness, fatigue, breast changes

Second Trimester (13-27 weeks)

• Baby: Rapid growth, movements felt
• You: Energy returns, bump grows

Third Trimester (28-40 weeks)

• Baby: Final development, prepares for birth
• You: Discomfort increases, nesting instinct

Important Reminders

• Due dates are estimates: Only 5% of babies arrive on time
• Every pregnancy is different: Don't compare experiences
• Regular prenatal care: Essential for monitoring health