Pregnancy Due Date & Week-by-Week Calculator
(Enter the first day of your last period)
(Only enter if you know the exact date of conception)
(Defaults to today, adjust if calculating for a different date)
Enter your dates and click "Calculate" to see your estimated due date and current pregnancy week.
Understanding Your Pregnancy Due Date & Week-by-Week Journey
A pregnancy calculator is an invaluable tool for expectant parents, helping to estimate the baby's due date and track the progress of the pregnancy week by week. While it provides a good estimate, it's important to remember that only about 5% of babies are born exactly on their due date.
How Does a Pregnancy Calculator Work?
Most pregnancy calculators rely on one of two key pieces of information:
- Last Menstrual Period (LMP): This is the most common method. Pregnancy is typically counted as 40 weeks (280 days) from the first day of your last menstrual period. This method assumes a regular 28-day menstrual cycle with ovulation occurring around day 14. This is often referred to as Naegele's Rule.
- Conception Date: If you know the exact date of conception (e.g., through IVF or precise tracking of ovulation), the due date is calculated as 38 weeks (266 days) from that date. This is because conception usually occurs about two weeks after the start of your LMP.
Our calculator prioritizes the Conception Date if provided, as it's generally more precise. Otherwise, it uses your LMP.
Why is Knowing Your Due Date Important?
Your Estimated Due Date (EDD) helps healthcare providers monitor your pregnancy, schedule important tests and screenings, and plan for your baby's arrival. It also gives you a timeline to prepare for the many changes ahead.
Tracking Your Pregnancy Week by Week
Beyond the due date, understanding your current pregnancy week is crucial. It allows you to:
- Monitor Fetal Development: Each week brings new milestones in your baby's growth and development.
- Anticipate Maternal Changes: You can better understand the physical and emotional changes you might experience.
- Plan for Appointments: Many prenatal appointments and tests are scheduled based on specific gestational weeks.
The Three Trimesters
Pregnancy is divided into three trimesters, each with its unique characteristics:
- First Trimester (Weeks 1-13): This period begins with conception and is marked by rapid fetal development, including the formation of major organs. Many women experience morning sickness and fatigue during this time.
- Second Trimester (Weeks 14-27): Often considered the "golden trimester," as many early pregnancy symptoms subside. The baby grows significantly, and you might start to feel movements.
- Third Trimester (Weeks 28-40+): The final stretch, where the baby gains weight rapidly and prepares for birth. You might experience increased discomfort, Braxton Hicks contractions, and anticipation for labor.
Disclaimer: This calculator provides an estimate based on standard medical formulas. For personalized medical advice and accurate dating, always consult with your healthcare provider. Ultrasounds in early pregnancy can provide a more precise due date.