Calculate Your Baby's Estimated Due Date
Whether you just found out you're pregnant or you've been tracking your cycle carefully, knowing your estimated due date helps you plan, prepare, and connect with each stage of your pregnancy journey. Our calculator supports four different input methods — last menstrual period, conception date, IVF transfer, and ultrasound dating — so you can use whichever information you have available.
Keep in mind that an estimated due date is just that — an estimate. Only about 5% of babies are born on their exact due date. Your healthcare provider will give you the most accurate dating based on your medical history and early ultrasound results.
When is your baby due?
Select the method that fits your situation best, then enter your dates to estimate your due date.
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How is a Due Date Calculated?
The most common method used by healthcare providers is Naegele's Rule, which adds 280 days (40 weeks) to the first day of your last menstrual period. This calculation assumes a 28-day cycle and ovulation on day 14. If your cycle is longer or shorter, your actual ovulation — and therefore your due date — may differ slightly.
IVF pregnancies use a different approach. Because fertilization (or in the case of frozen embryos, the equivalent of fertilization) is known precisely, due date calculations are highly accurate. A 5-day blastocyst transfer is dated as if fertilization occurred 5 days before transfer.
Ultrasound dating in the first trimester is considered very accurate — often within 5 to 7 days. Your doctor may adjust your due date based on ultrasound measurements, especially in early pregnancy.
This calculator offers a general estimate based on the information you provide. Every pregnancy is unique, and due dates can change based on ultrasound measurements and your healthcare provider's assessment. Please confirm your due date with your OB-GYN, midwife, or healthcare provider. This tool is for informational and planning purposes only and is not a substitute for professional medical care.