How accurate are due date calculations?

Due date calculations are estimates. Only about 5% of babies are born on their exact due date. Most babies are born within 2 weeks before or after the estimated due date, which is considered full-term.

What if I have irregular cycles?

If you have irregular cycles, dating by LMP may be less accurate. Your healthcare provider may use ultrasound measurements, especially in early pregnancy, to provide a more accurate due date estimate.

Pregnancy Calculator – Due Date Calculator

Calculate your pregnancy due date, current week, and important milestones based on your last menstrual period or conception date.

Pregnancy Calculator – Due Date Calculator

Calculate your pregnancy due date, current week, and important milestones based on your last menstrual period or conception date.

Last Menstrual Period*

First day of your last menstrual period

Cycle Length (days)

Average length of your menstrual cycle

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Enter your last period date to see pregnancy progress

Understanding Pregnancy Dating

Pregnancy dating is typically calculated from the first day of your last menstrual period (LMP), even though conception usually occurs about 2 weeks later. This method provides a standard 40-week pregnancy timeline used by healthcare providers worldwide.

Due Date = LMP + 280 days (40 weeks)