Pregnancy Due Date Calculator

An estimated due date is exactly that—an estimate. Only about 4% of babies are born on their exact due date. Most babies are born within a window of two weeks before or two weeks after the estimated date, which is considered a normal full-term pregnancy.

Standard due date calculations assume a regular 28-day menstrual cycle, with ovulation occurring on Day 14. If your cycle is shorter or longer (e.g. 35 days), ovulation occurs later, meaning your due date will be shifted. The calculator automatically adjusts the due date by adding or subtracting the variance from a 28-day cycle.

For In Vitro Fertilization (IVF) transfers, the due date is calculated based on the embryo transfer date and the age of the embryo. For a 3-day embryo transfer, the due date is transfer date + 263 days. For a 5-day blastocyst transfer, the due date is transfer date + 261 days.

Early ultrasounds (usually performed in the first trimester between weeks 8 and 14) measure the crown-rump length (CRL) of the embryo. This is considered the most accurate method to date a pregnancy, especially for women with irregular menstrual cycles. If the ultrasound estimate differs from the LMP date by more than 7 days, your doctor may adjust your official due date.

A pregnancy due date calculator estimates your baby's expected delivery date based on information such as the first day of your last menstrual period (LMP), conception date, or IVF transfer date. It provides an approximate timeline for pregnancy milestones and fetal development.

A full-term pregnancy typically lasts about 40 weeks (280 days) from the first day of the last menstrual period. Most babies are born between 37 and 42 weeks of pregnancy.

Yes. If you know your conception date, your estimated due date is generally calculated by adding approximately 266 days (38 weeks) to that date. This method can be useful when the conception date is known with reasonable certainty.

Naegele's Rule is a common method used to estimate a due date. It calculates the expected delivery date by adding one year, subtracting three months, and adding seven days to the first day of the last menstrual period.

Yes. Due dates are estimates, and many babies are born before or after the calculated date. Deliveries between 37 and 42 weeks are generally considered within the normal full-term range.

Pregnancy is divided into three trimesters. The first trimester covers weeks 1–13, the second trimester covers weeks 14–27, and the third trimester covers weeks 28–40. Your due date calculation can help determine your current trimester.

Yes. Women with irregular menstrual cycles may ovulate earlier or later than average, which can affect due date estimates based solely on the last menstrual period. In such cases, ultrasound dating often provides greater accuracy.

The estimated due date calculation is generally the same for singleton and multiple pregnancies. However, twins and other multiples are often born earlier than the calculated due date and may require closer medical monitoring.

Many healthcare providers recommend an ultrasound during the first trimester, typically between 8 and 14 weeks of pregnancy. Early ultrasounds help confirm pregnancy dating and assess fetal development.

No. A pregnancy due date calculator provides an estimate for informational purposes only. Always consult your doctor, obstetrician, or healthcare provider for accurate pregnancy assessments, prenatal care, and medical guidance.