How to Calculate My Conception

Women of childbearing age not on birth control are usually fertile for somewhere between four and seven days per month. The more regular your cycle is--if it takes the same number of days each month--the easier it is to track when you may have conceived. When you go to the doctor, he or she will calculate your likely date of conception and due date based on the first day of your last period and other information. You can calculate your conception on your own. Remember that a due date is an estimate--women often give birth before and after their official due date.

Things You'll Need

• Calendar
• Computer
• Pen

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Instructions

• 1

  Mark the date of the first day of your most recent menstrual cycle on your calendar. Mark the times you had intercourse since then if you remember them.

• 2

  Go to a conception calculator online (see link below). You can now calculate the probable date of conception based on two pieces of information: your due date, and the first day of your last menstrual period.

• 3

  Select either the "Due Date" or "First Day of LMP" option in the drop down box in step one. Enter the appropriate date and click "Calculate."

• 4

  Check the date or range of dates against the days when you had intercourse. For example, if it gives you a range of four days, you may be able to mark on your calendar which of those four days you think you conceived.

• 5

  Set up an appointment with a doctor for a checkup.