Pregnancy Due Date Calculator

Last Menstrual Period (LMP) Method

The LMP method estimates the due date based on the first day of the woman’s last menstrual period. It assumes a standard pregnancy duration of 280 days (40 weeks) from this date, adjusted for variations in menstrual cycle length.

Formula

Due Date = LMP + 280 − ( Standard Cycle Length − Actual Cycle Length )

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Conception Date Method

This method estimates the due date based on the date of conception, assuming a pregnancy duration of 266 days (38 weeks) from conception.

Formula

Due Date = Conception Date + 266
$\text{Due Date} = \text{Conception Date} + 266$

Ultrasound Method

The ultrasound method estimates the due date based on the gestational age determined during an ultrasound examination. It subtracts the estimated gestational age (in weeks and days) from 280 days (40 weeks).

Formula

Due Date = Ultrasound Date + 280 − ( Gestational Weeks × 7 + Gestational Days )$\text{Due Date} = \text{Ultrasound Date} + 280 – (\text{Gestational Weeks} \times 7 + \text{Gestational Days})$

In Vitro Fertilization (IVF) Method

For pregnancies resulting from IVF, the due date is estimated similarly to the conception date method, assuming a pregnancy duration of 266 days (38 weeks) from the date of embryo transfer.

Formula

Due Date = Embryo Transfer Date + 266$\text{Due Date} = \text{Embryo Transfer Date} + 266$