Everybody has a different amount of blood in it, depending on where we live and the size of the persons body. If you weigh 80 pounds you will probably have 2.5 quarts of blood but 160 pound person will have about 5 quarts. Infants (about 1 month old) only have have 10 ounces of blood. If places with less oxygen in the air, higher altitudes, cause people to have about 2 quarts more blood. This blood allows the body to capture extra oxygen that the body needs to work and grow.