Mount Everest is still growing about a quarter inch higher every year

Mount Everest already stands as the highest point on Earth, its summit reaching roughly 8,849 meters above sea level. What surprises many people is that the mountain is not finished growing. Measurements show its peak creeping upward year after year, a slow rise driven by the same colossal forces that raised the Himalayas in the first place.

The push comes from a continental collision that has been underway for tens of millions of years. The Indian tectonic plate is driving north into the Eurasian plate, crumpling the crust between them into the tallest mountain range on the planet. That collision has not stopped, so the range keeps rising, and Everest rides upward along with it at a pace usually described as a few millimeters a year.

The collision that built the Himalayas

Around 50 million years ago, the landmass of India, drifting north on its tectonic plate, began to ram into Asia. Where oceanic crust would normally slide down into the mantle, the two continental plates were too buoyant to sink, so the rock had nowhere to go but up and sideways. The result was the Himalayas, a range still being squeezed higher as India continues to advance by several centimeters a year. That relentless convergence is the underlying engine behind Everest’s continued growth, thrusting the entire region skyward over geologic time.

How fast the summit is rising

Pinning down an exact rate is difficult, because uplift is partly offset by erosion wearing the peak down. Satellite positioning and ground surveys place the tectonic uplift of the summit at a few millimeters per year, and popular summaries often round the figure to about a quarter inch annually. As a detailed overview of the mountain notes, a joint China and Nepal survey in 2020 revised the official height slightly upward to 8,848.86 meters, reflecting both improved measurement and the ongoing rise. The growth is small on any human timescale but adds up to meters over thousands of years.

An unexpected boost from a distant river

Tectonics alone may not tell the whole story. Researchers reported in 2024 that erosion by a river network some 75 kilometers away has been carving out a deep gorge, stripping a large mass of rock from the region. According to an account of that study, the loss of all that weight lets the crust flex upward, a rebound effect that could be lifting Everest by an extra fraction of a millimeter each year. The team estimated the process has already added something on the order of 15 to 50 meters to the mountain’s height.

The rebound effect explained

That distant-river mechanism relies on a principle called isostasy. The rigid crust essentially floats on the denser, slowly flowing mantle beneath it, like a raft on water. When a river erodes away millions of tons of rock, the load pressing down on the crust decreases, and the lightened section springs slowly upward to a new balance. The same effect is why land once buried under Ice Age glaciers is still rising today, thousands of years after the ice melted. At Everest, isostatic rebound appears to be stacking a modest extra lift on top of the tectonic push.

Why erosion keeps the numbers modest

The mountain is not simply gaining height unopposed. Wind, ice, landslides and rivers constantly grind away at the peaks, and major earthquakes can drop a summit by a small amount in a single event, as the 2015 Nepal earthquake illustrated across parts of the range. The height recorded on any given day reflects the balance between uplift adding rock from below and erosion carrying it away from above. For now the uplift has the edge, which is why the roof of the world continues its slow, steady climb.

Measuring a mountain that keeps changing

Determining Everest’s exact height has challenged surveyors for nearly two centuries. The first widely accepted figure came from the Great Trigonometrical Survey of India in the nineteenth century, which used precise angle measurements taken from distant stations across the plains to calculate the peak’s elevation, an astonishing feat of mathematics for its era. Modern efforts rely on satellite positioning equipment carried to the summit itself, along with ground-penetrating radar to distinguish the rock summit from the snow and ice piled on top of it. That distinction matters, because the depth of snow at the peak varies from season to season, and different countries have at times reported slightly different numbers depending on whether they measured to the snow cap or the rock beneath. The joint survey by China and Nepal that produced the current official figure of 8,848.86 meters was designed in part to reconcile those differences with a single agreed measurement. Because the mountain is simultaneously being pushed up by tectonics, lifted by isostatic rebound and worn down by erosion, no single number is ever permanent. Each careful resurvey captures a snapshot of a peak in slow motion, a reminder that even the most fixed-seeming landmark on the planet is, on the timescales that shape the Earth, very much a work in progress.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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