World Rugby rankings are calculated using a points exchange system. When two teams play each other, points are exchanged based on the result, the margin of victory, and the relative ranking of the two teams. A win against a higher-ranked team yields more points than a win against a lower-ranked team.
Rankings are updated after every international match. Home advantage is factored in — the home team is treated as if they are three places higher in the rankings for the purposes of the points calculation. Rankings only apply to full international matches between World Rugby member unions.