The total area of the atoll is about . The lagoon area is roughly  with depths ranging down to about . The total land area (excluding peripheral reefs) is around . The coral reef surrounding the seaward side of the atoll is generally broad, flat, and shallow around  below mean sea level in most locations and varying from  in width. This fringing seaward reef shelf comprises an area around . At the outer edge of the reef shelf, the bottom slopes very steeply into deep water, at some locations dropping to more than  within  of the shore.