Start counting from the first day of your last menstrual period
Count each completed 7-day period as 1 week
Use the current date to calculate how many weeks have passed since that first day
If you know your conception date, add about 2 weeks to estimate pregnancy weeks
Use an online pregnancy calculator or calendar for a quick check
Confirm your gestational age with an ultrasound if needed
Ask your healthcare provider to verify your due date and week count