Pregnancy Calculator

Enter the date of your last menstrual period and the number of days in your menstrual cycle into the pregnancy calculator, and click on the Calculate button. Other calculations are optional – use them when needed. On average, there are 28 days in a menstrual cycle, but it can last from as little as 22 to as many as 44 days. The Pregnancy Calculator takes your menstrual cycle into account when calculating the due date and the conception date.