FactSentinel

Mount Everest is the tallest mountain above sea level, but it is not the tallest when measured from base to peak. That distinction belongs to Mauna Kea in Hawaii. Mauna Kea rises about 10,200 meters (roughly 33,500 feet) from its base on the Pacific Ocean floor to its summit, while Everest stands about 8,849 meters (29,032 feet) above sea level and rises roughly 3,600 to 5,200 meters from the surrounding Tibetan Plateau, depending on where the base is defined.

The difference comes down to what is being measured. Mauna Kea's summit reaches only about 4,207 meters above sea level, so most of the volcano is hidden beneath the ocean. Its base sits deep on the seafloor, where the weight of the volcano has also pushed the crust downward. Measured from that base, Mauna Kea exceeds Everest by well over a thousand meters. Everest's height is the standard figure because elevation above sea level is the most common and consistent reference point for comparing mountains on land.

A common misconception is that "tallest" has a single meaning. In fact, mountains are ranked in three ways. Everest has the highest elevation above sea level. Mauna Kea has the greatest height from base to peak. Ecuador's Chimborazo has the summit farthest from Earth's center, because the planet bulges at the equator. Everest wins only one of these categories, so the claim is false.