What is the highest mountain above sea level, according to official surveys?

Mount Everest is the highest mountain above sea level, with an official elevation of 8,848.86 metres.

Everest stands in the Himalayas on the Nepal–China border. Nepal calls it Sagarmatha, while Tibetans call it Qomolangma. The mountain was named in English after George Everest, a former Surveyor General of India, although he never saw it.

The first confirmed ascent reached the summit on 29 May 1953, when New Zealander Edmund Hillary and Sherpa Tenzing Norgay climbed from the Nepalese side. Earlier expeditions had attempted the mountain, including the 1924 expedition during which George Mallory and Andrew Irvine disappeared.

Everest is not the tallest mountain when measured from its base: Mauna Kea extends farther from ocean floor to summit. Chimborazo is also farther from Earth’s centre because of the planet’s equatorial bulge.