Due Date Calculator

Trimesters Overview

• First Trimester (Weeks 1-12): Major organ development begins. Morning sickness is common. The heart starts beating around week 6. By week 12, all major organs and body systems have formed.
• Second Trimester (Weeks 13-27): Often called the "golden period" as many early symptoms ease. Movement can be felt around weeks 16-20. Gender can typically be determined by ultrasound around week 20.
• Third Trimester (Weeks 28-40): Rapid growth and development. The baby gains most of its birth weight. Lungs mature. The baby typically moves into a head-down position in preparation for birth.

Key Milestones

• Week 4: Implantation occurs, pregnancy test may turn positive
• Week 6: Heartbeat may be detected on ultrasound
• Week 12: End of first trimester, risk of miscarriage drops significantly
• Week 20: Anatomy scan, halfway point
• Week 24: Viability milestone
• Week 37: Considered "early term" (full term is 39-40 weeks)
• Week 40: Estimated due date

Cycle Length Adjustment

The standard due date calculation assumes a 28-day menstrual cycle with ovulation occurring on day 14. If your cycle is longer or shorter, the calculator adjusts accordingly. For example, a 35-day cycle means ovulation likely occurred around day 21, so the due date shifts forward by about 7 days.

Disclaimer: This calculator provides estimates for informational purposes only. Only your healthcare provider can confirm your due date, typically through ultrasound measurements. Consult your doctor or midwife for personalized prenatal care.