This complimentary calculator calculates key pregnancy dates using intervals published by US Department of Health & Human Services.

To calculate your due date, enter the first day of your last period:

If you know that your cycle is shorter or longer than 28 days, please adjust the number:

Calculation Results

Probable date of ovulation:

Your baby's fetal organ formation begins:

Your baby's major organs formed:

Begin 2nd trimester:

Begin 3rd trimester:

Due date: