When you become pregnant, knowing your baby's due date can help you plan for its arrival. The March of Dimes notes that the typical pregnancy lasts 280 days, or 40 weeks, but your actual due date will vary depending on the length of your menstrual period and personal health. Your baby's due date gives you a general idea of when your baby may make his first appearance in the world so you can plan prenatal care and home preparations accordingly.
Step 1
Write down the first day of your last period. Although you technically don't become pregnant until halfway through your cycle, you need to use the first date of your period as a starting point to calculate your baby's due date. Few people actually know the date of conception, notes Baby Center. The first day of your last period signifies the beginning of your cycle and makes it easier to find the date of conception.
Step 2
Add seven days to the first date. For instance, if the first day of your last period was on the 9th, add seven days to get the 16th.
Step 3
Add nine months to the month of the first day of your last period. If your last period started on March 9, then you'll count forward nine months to get December.
Step 4
Add the number from Step 2 to the month in Step 3 to get Dec. 16. This is your baby's estimated due date.
Step 5
Check your results using online calculators like those found at the March of Dimes and American Pregnancy Association websites. Both calculators can use the first date of your last period or the date of conception to find out when your baby is due without needing to do the calculations yourself.
Things You'll Need
- Pen
- Paper
