Reverse Due Date Calculator to Calculate Conception Dates
This free online conception calculator will determine the conception date -- including the day of the week -- based on your pregnancy due date, ultrasound, or the 1st day of your last menstrual period (LMP).
Plus, unlike other conception calculators, this calculator includes selectable dates dating back 100 years, which means it can also be used to calculate conception dates and days of the week for any dates of birth occurring within the past 99 years.
Want to know what date and day of the week you were likely conceived on? Simply select your birthday (or due date if you were born premature or late) and click the "Calculate Conception Date" button.
Note that if you want to calculate what date your baby is due to be born on (EDD), please visit the Pregnancy Due Date Predictor -- which also includes How to Calculate Due Date based on Naegele's Rule.
Or, if you'd like to track your (or a loved one's) pregnancy term, be sure to visit the Pregnancy Countdown Calculator, which tells you the days, weeks, and months along and remaining. It also includes a countdown meter and printable calendar.
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