Chinese Foreign Minister Wang Yi and his Nepalese counterpart, Pradeep Gyawali, simultaneously pressed buttons during a virtual conference and the new height flashed on the screen.
The height of Everest, which is on the border between China and Nepal, was agreed on after surveyors from Nepal scaled the peak in 2019 and a Chinese team did the same in 2020.
There had been debate over the actual height of the peak and concern that it might have shrunk after a major earthquake in 2015. The quake killed 9,000 people, damaged about 1 million structures in Nepal and triggered an avalanche on Everest that killed 19 people at the base camp.
There was no doubt that Everest would remain the highest peak because the second highest, Mount K2, is only 8,611 meters (28,244 feet) tall.
Everest's height was first determined by a British team around 1856 as 8,842 meters (29,002) feet.
But the most accepted height has been 8,848 meters (29,028 feet), which was determined by the Survey of India in 1954.
In 1999, a National Geographic Society team using GPS technology came up with a height of 8,850 (29,035 feet). A Chinese team in 2005 said it was 8,844.43 meters (29,009 feet) because it did not include the snow cap.
A Nepal government team of climbers and surveyors scaled Everest in May 2019 and installed GPS and satellite equipment to measure the peak and snow depth on the summit.
Chinese President Xi Jinping visited Nepal later that year and the leaders of the two countries decided that they should agree on a height.
A survey team from China then conducted measurements in the spring of 2020 while all other expeditions were canceled due to the coronavirus pandemic.
Nepal's climbing community welcomed the end of confusion over the mountain's height.
“This is a milestone in mountaineering history which will finally end the debate over the height and now the world will have one number,” said Santa Bir Lama, president of the Nepal Mountaineering Association.
China's official Xinhua New Agency quoted Xi as saying the two sides are committed to jointly protecting the environment around Everest and cooperating in scientific research.
For China, the announcement appeared to be as much about politics as geography. China has drawn Nepal ever closer into its orbit with investments in its economy and the building of highways, dams, airports and other infrastructure in the impoverished nation.
That appears to serve China’s interests in reducing the influence of rival India, with which it shares a disputed border, and Nepal’s role as a destination for refugee Tibetans.
The Xinhua report said nothing about the technical aspects but heavily emphasized the joint announcement’s geopolitical weight.
China and Nepal will establish an “even closer community of a shared future to enrich the countries and their peoples,” Xinhua quoted Xi as saying.