Pregnancy Due Date Calculator
Calculate your baby's estimated due date and track your pregnancy journey
Enter the first day of your last menstrual period to calculate your estimated due date and pregnancy progress.
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Back to Finance CalculatorsUnderstanding Your Due Date
A pregnancy due date calculator helps estimate when your baby will arrive based on the first day of your last menstrual period (LMP) or conception date. The standard pregnancy duration is 280 days or 40 weeks from the LMP, though only about 5% of babies arrive exactly on their due date. Most healthy pregnancies deliver between 37 and 42 weeks.
Our calculator uses Naegele's Rule, the standard medical method for estimating due dates: add 7 days to your LMP, subtract 3 months, and add one year. For example, if your LMP was January 15, 2024, your estimated due date would be October 22, 2024. Healthcare providers may adjust this date after ultrasound measurements, which are most accurate in the first trimester.
Understanding your due date helps you track pregnancy milestones, schedule prenatal appointments, and prepare for your baby's arrival. The calculator also shows your current trimester and pregnancy week. Remember that due dates are estimates—your baby will arrive when ready. Regular prenatal care ensures healthy pregnancy monitoring regardless of the exact delivery date.
Frequently Asked Questions
How accurate is the due date calculator?
Due date calculators provide estimates within 1-2 weeks of the actual delivery date. Only 5% of babies arrive exactly on their due date, while 90% are born within 2 weeks before or after. First-trimester ultrasounds are the most accurate dating method, with precision within 5-7 days. Due dates based on LMP assume a 28-day cycle and may be less accurate for irregular cycles.
When are the three trimesters of pregnancy?
Pregnancy is divided into three trimesters. The first trimester spans weeks 1-13, characterized by rapid fetal development and common morning sickness. The second trimester (weeks 14-27) is often the most comfortable period, with energy returning and baby movements beginning. The third trimester (weeks 28-40) involves final growth and preparation for birth, with increased discomfort as baby grows.
What if I don't remember my last menstrual period?
If you don't remember your LMP, your healthcare provider will estimate your due date using an early pregnancy ultrasound, which measures the fetus to determine gestational age. This is typically done between 8-13 weeks and is highly accurate. If you know your conception date (from fertility treatments or specific timing), you can use that method instead—add 266 days to the conception date.
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