Until now the countries differed over whether to add the snow cap on top. The new height is 8848.86 metres.
China's previous official measurement of 8844.43m had put the mountain nearly four metres lower than Nepal's.
Everest stands on the border between China and Nepal and mountaineers climb it from both sides.
Officials at Nepal's foreign ministry and department of survey said surveyors from both countries had co-ordinated to agree on the new height.