Due Date Calculator

Calculate From

Last Period Conception Date IVF Transfer

First Day of Last Menstrual Period

Average Menstrual Cycle Length

days

Average cycle length is 28 days, but can vary from person to person

Conception Date

This is the estimated date of conception (ovulation or insemination)

Embryo Transfer Date

The date of embryo transfer for IVF pregnancies

Your Due Date

About Due Date Calculation

Important notes about due dates:

Only about 4% of babies are born on their exact due date
Most babies arrive between 38 and 42 weeks of pregnancy
First-time mothers often deliver later, closer to 41 weeks
Due dates are estimates and may be adjusted based on ultrasound measurements

Understanding Due Date Calculation

Your estimated due date (EDD) is a crucial date in your pregnancy journey, but it's important to understand that it's just that—an estimate. Only about 4-5% of babies are born exactly on their due date, with most arriving within two weeks before or after this date. Your healthcare provider will use your EDD as a reference point for monitoring fetal development, scheduling prenatal tests, and making decisions about interventions if your pregnancy goes past term.

How Due Dates Are Calculated:

Naegele's Rule: The most common method, calculates your due date by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). This assumes a 28-day cycle with ovulation occurring on day 14.
Conception Date: If you know your conception date, your due date is approximately 266 days (38 weeks) from that date.
IVF Transfer: For IVF pregnancies, due dates are calculated based on the age of the embryo and the transfer date.
Ultrasound Dating: Early ultrasounds (especially before 14 weeks) can provide the most accurate estimate of gestational age and due date.

Term Definitions:

Early Term: 37 weeks 0 days to 38 weeks 6 days
Full Term: 39 weeks 0 days to 40 weeks 6 days
Late Term: 41 weeks 0 days to 41 weeks 6 days
Post Term: 42 weeks 0 days and beyond

Important Note

This calculator provides an estimate based on standard pregnancy calculations. Your healthcare provider may adjust your due date based on ultrasound measurements or other clinical factors. Always rely on your healthcare provider's guidance for your specific situation, especially regarding timing of delivery and when to seek care if you go past your due date.

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Preparing for Baby's Arrival

While your due date provides a target for your baby's arrival, preparing for some flexibility is essential. Creating a birth plan that outlines your preferences while remaining open to adjustments can help you feel more in control. Consider discussing with your healthcare provider what interventions might be suggested if you go past your due date, including monitoring options and potential induction. Many healthcare providers begin these conversations around week 38-39. Having this information in advance can help you make informed decisions if your pregnancy extends beyond your estimated due date.

The weeks leading up to your due date are an ideal time to prepare practically for your baby's arrival. Gathering essential baby items, preparing your home, installing car seats, and packing a hospital bag by 36-37 weeks can reduce last-minute stress. Many expectant parents also find it helpful to prepare some frozen meals, arrange for help after birth, and plan for pet care if needed. If you have other children, discussing the new baby's arrival and making arrangements for their care during labor and delivery is important. Having these practical matters organized can bring peace of mind as your due date approaches.

Taking care of yourself physically and emotionally in the final weeks of pregnancy is equally important. While the waiting period can feel challenging, focusing on rest, gentle movement, and activities you enjoy can make this time more comfortable. Many find that maintaining regular prenatal appointments, staying hydrated, continuing safe physical activity, and practicing relaxation techniques can be beneficial. Some expectant parents use this time to connect with their baby through talking, singing, or reading aloud. Remember that whether your baby arrives before, on, or after your due date, your body and baby are working together to determine the optimal timing for birth.