Due Date Calculator
The Due Date Calculator helps estimate the delivery date of a pregnant woman based on several methods: last menstrual period (LMP), ultrasound, conception date, or IVF transfer date.
Modify the values below and click "Calculate" to determine the estimated due date.
Estimate Based On:
Last Menstrual Period (LMP):
Conception Date (if known):
IVF Transfer Date (if applicable):
Related Resources
How Due Dates Are Calculated
The due date, also called the Estimated Date of Confinement (EDC), represents the approximate date a pregnant woman is expected to deliver. It is important to note that due dates are only estimates; fewer than 5% of births occur exactly on the due date.
Estimation Methods
1. Last Menstrual Period (LMP):
The standard method assumes pregnancy lasts 280 days (40 weeks) from the first day of the last menstrual period. This calculation is simple but assumes a regular 28-day cycle.
2. Ultrasound:
Ultrasound uses sound waves to estimate the gestational age by measuring the fetus's development. This method is particularly accurate early in the pregnancy.
3. Conception Date:
The due date is calculated by adding 266 days to the conception date. This method is most useful when the exact date of conception is known.
4. IVF Transfer Date:
For pregnancies conceived via IVF, the due date is estimated based on the embryo transfer date and the embryo's age at transfer (3-day or 5-day).
Understanding the Due Date Range
Early-term: 37-39 weeks
Full-term: 39-41 weeks
Late-term: 41-42 weeks
Post-term: Beyond 42 weeks
Most babies are born between 37 and 42 weeks. Doctors use this range to monitor the pregnancy and ensure the health of both the baby and the mother.