How to Determine Nationalities and What Percentage of Each are in a Family Tree

Learning more about your family history, including the countries your ancestors came from, is an enlightening experience that teaches you more about yourself. Your research will also bring you closer to members of your family tree who passed on long before you were born. Discovering your ancestor's nationalities and what percentage of each you inherited is a simple process once you gather a few important pieces of information.

Gather the information you already know about your family, including names and birthplaces. Start with your parents and grandparents, or go further back if you desire.

Use online tools from organizations like Family Search to see if your genealogy has already been done. Also check with any surviving relatives to get the information you need. Search census records as well as birth, marriage and death certificates.

Determine your percentage of each nationality by dividing the percentage of your parents' nationalities by two, your grandparents' by four, great grandparents' by eight, and so on. For example, if your paternal grandmother is 100 percent Danish, this means that your father is 50 percent Danish, and you are 25 percent Danish.

For a more complicated example, suppose that your mother is 100 percent Irish and your father is 50 percent Danish, 25 percent Irish and 25 percent Welsh. You are 62.5 percent Irish (100 from your mother plus 25 from your father divided by two equals 62.5). You are 25 percent Danish (50 percent from your father and 0 percent from your mother) and 12.5 percent Welsh (25 from your father and 0 from your mother).