Note the first day of your last menstrual period (LMP)
Count 40 weeks from the first day of your LMP to estimate your due date
Count 280 days from the first day of your LMP to estimate your due date
Count the weeks and days since the first day of your LMP to estimate your current pregnancy age
Use an ovulation date if known: add 38 weeks or 266 days to estimate your due date
Use a pregnancy calculator or calendar to track weeks and months
Confirm the estimated due date with an ultrasound if recommended by a healthcare professional