Free pregnancy calculator to find your due date, current week, trimester, and baby milestones based on LMP, conception, or ultrasound.
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Expecting a baby? Our pregnancy calculator helps you determine your estimated due date, track your current pregnancy week, understand which trimester you're in, and see important milestones throughout your pregnancy journey. Get accurate calculations using your last menstrual period, conception date, or ultrasound results.
Pregnancy is typically 40 weeks (280 days) from the first day of your last menstrual period (LMP). This is Naegele's Rule, the standard method doctors use. Your conception date is usually about 14 days after your LMP (during ovulation). Pregnancy is divided into three trimesters, each about 13 weeks long, with distinct developmental milestones for your baby.
Due Date Calculation (Naegele's Rule)
Due Date = LMP + 280 daysCalculate from LMP, conception date, or ultrasound results for maximum flexibility.
See exactly which week and trimester you're in, plus days remaining until your due date.
View key dates like trimester transitions, recommended ultrasounds, and viability milestones.
Just found out you're pregnant? Calculate your due date and see which week you're in.
Know when to expect important appointments, tests, and prepare for your baby's arrival.
Compare your calculated due date with ultrasound dating to ensure consistency.
Keep family and friends updated on your pregnancy progress and important dates.
The calculator provides an estimated due date. Only about 5% of babies are born on their exact due date, but 90% are born within two weeks before or after. Your healthcare provider may adjust your due date based on ultrasound measurements, which are most accurate in the first trimester.
You can calculate as soon as you know your LMP date. However, your doctor will likely confirm or adjust the due date based on your first trimester ultrasound (usually around 8-13 weeks), which is the most accurate method for dating a pregnancy.
If you're unsure of your LMP, try using the conception date method if you know approximately when conception occurred. Otherwise, your healthcare provider can estimate gestational age using an early ultrasound measurement.
Pregnancy weeks are counted from the first day of your last menstrual period, not from conception. This means you're technically "2 weeks pregnant" before conception even occurs. This is standard medical practice and why pregnancy is 40 weeks instead of 38.
First trimester (weeks 1-12): Major organs form, morning sickness is common. Second trimester (weeks 13-26): You feel movement, anatomy scan occurs. Third trimester (weeks 27-40): Baby gains weight rapidly, you prepare for birth. Each trimester has unique symptoms and developments.