Due Date Calculator

How the Due Date is Estimated

This calculator provides an estimated due date (EDD) for your pregnancy based on the first day of your last menstrual period (LMP). This is a common method used by healthcare professionals to get an initial estimate.

Naegele's Rule:

The calculation is typically based on Naegele's rule, which works as follows:

• Start with the first day of your Last Menstrual Period (LMP).
• Add one year.
• Subtract three months.
• Add seven days.

This rule assumes a typical 28-day menstrual cycle with ovulation occurring on day 14. The total estimated pregnancy duration is 280 days, or 40 weeks, from the LMP.

Gestational Age:

The calculator also shows the current gestational age, which is how far along you are in your pregnancy, calculated in weeks and days from your LMP.

Factors Affecting Due Date Accuracy:

• Irregular Menstrual Cycles: If your cycles are not consistently 28 days, or if you don't know your LMP, Naegele's rule may be less accurate.
• Date of Conception: If the exact date of conception is known (e.g., through assisted reproductive technologies), it can provide a more precise due date.
• Early Ultrasound: An ultrasound performed in the first trimester is often considered the most accurate method for dating a pregnancy and may be used by your doctor to adjust your EDD.

Important Disclaimer: The due date provided by this calculator is an estimate only. Very few babies are born on their exact due date. Your actual delivery date can vary. Always consult with your healthcare provider (doctor or midwife) for accurate due date information, ongoing prenatal care, and to discuss any concerns you may have about your pregnancy.