If you're keeping tabs on how tall Mount Everest is, make sure to refresh the page you had open from the last time you checked. Due to tectonic pressure, weathering, and earthquakes (especially a major 2015 temblor), among other factors, the world's highest mountain is constantly experiencing a slight shift up or down in height. But on Tuesday, Nepal and China, which flank Everest on either side, jointly announced they'd come to a rare agreement on how tall Everest is, presenting the number the Nepal Times says has been guarded "as if it was a military secret": 29,032 feet, or 8,848.86 meters—a slight bump over Nepal's previous figure, but more than 13 feet over what China had previously registered. The two countries had been at odds on the mountain's height because China had been measuring only rock height, while Nepal included the snow cap on the mountain's peak.
China came to its previous measurement in 2005, but Nepal has long wanted its own figures, per the BBC. A Nepalese surveyors team underwent a two-year training before measuring Everest; Chinese surveyors, meanwhile, did their own recalculations on their side of the mountain, the Independent reports. The process is an elaborate one: It first involves determining where the base of the mountain is using its mean sea level (which countries often differ on), then applying GPS figures and various trigonometry calculations based on a network of surrounding peaks leading up to a surveyor's beacon at the summit. The Times features a timeline of the various heights registered for Everest since 1856, when surveyors found it to be exactly 29,000 feet. Survey leader Sir George Everest thought the round number sounded too odd, so he added 2 feet to that, making the official original measurement 29,002 feet. (Read more Mount Everest stories.)