You can trace your family tree to glean knowledge or entertain yourself, but discovering you're related to a member of the British royal family is conversational gold. Simple mathematics dictates that you have a good chance of finding out you're related to royalty because of the sheer amount of ancestors you have. You can start with your four grandparents, eight great-grandparents, and sixteen great-great-grandparents, but if you go back forty generations, you'll find over one trillion ancestors. Learning where to sift through this vast number can help you determine whether you really are related to British royalty.
Before you dig in to your research, you'll need Ancestral File Numbers for your relatives. On Family Search, type the names of your parents, grandparents or great-grandparents into the main search field, and include their birth years and places of birth if possible. Look for matches under "Ancestral File," and click on the record if one appears. Note the numbers next to "AFN" -- these are the Ancestral File Numbers you'll need.
Visit Digital Roots' Relative Finder. This website can be used to search directly for royalty in your ancestry. Choose the first option, "I want to see how I'm related to notable historic individuals" and enter an Ancestral File Number that you obtained in Step 1.
Click "Finished" after entering your relative's AFN into the website. Select the groups you wish to search for, such as "Kings and Queens." Click on "Request Report" to have the site find matches in your ancestry. See if you're related to royalty. Even if you don't recognise any members of the British royal family on your list, look for Charlemagne, who had twenty children and thus has a prestigious family tree. He was King of the Franks from the year 768 and Emperor of the Romans from 800.
Use family tree websites such as Ancestry, Family Search and Genes Reunited to build your family tree as much as possible. Using census records and birth, marriage and death indexes, construct your family tree as far back as possible. Spend time researching until you uncover more family members. If you can find their Ancestral File Numbers, make note of them.
Enter any new information you can find into Relative Finder. If your first search wasn't successful, using an older relative's Ancestral File Number can turn up better results. Remember, the chances are good that anybody of European descent is related to the royal family if you go back far enough.
Use Royalist to search through genealogical information for the British royal family. The website has a database of all people who have been connected to the royal family, and it also has a Royalty Kinship calculator that you can use to find royal ancestors, but you'll need to sign up for that service.