Pregnancy Week Calendar By Due Date. Use our pregnancy calculator by plugging in the date of your last period, the date you conceived if you know it, the timing of your ivf transfer, or your first ultrasound date. Your due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (assuming a 28 day cycle).

Plus, explore the exciting milestones ahead. When is my due date? find out when you’re due, how many weeks you are, how big the baby is, and much more with the mama natural due date calculator.