Due Date Calculator
This due date calculator can be used to estimate the due date based on biological cycles.
Also check the pregnancy calculator.
The result of this due date calculator are only an estimation based on average. The actual length of pregnancy depends on various factors. For example, the first pregnancy tends to last longer than subsequent pregnancies. Fewer than 10% of births occur on the due date; 50% of births are within a week of the due date, and almost 90% within two weeks.
Though pregnancy begins at conception, it is more convenient to date from the first day of a woman's last menstrual period (LMP), or from the date of conception (if known). Starting from one of these dates, the expected due date can be calculated. Counting from the LMP, pregnancy usually lasts between 37 and 42 weeks, with the due date at 40 weeks, 38 weeks after conception. 40 weeks is a little more than nine months and six days or 10 lunar months.
An early sonograph can determine the age of the pregnancy fairly accurately. In practice, doctors typically express the age of a pregnancy (i.e. an "age" for an embryo) in terms of "menstrual date" based on the first day of a woman's last menstrual period.
