Mont Blanc measured at 4,807.47 metres, up 1.88 metres on 2023 but down on 2025

A new reading of the summit

Surveyors from the Haute-Savoie chamber of surveyors measured the summit of Mont Blanc on 17 September, and they presented the results in Saint-Gervais on Wednesday, 14 October. The new height is 4,807.47 metres above sea level. Against the 4,805.59 metres recorded in 2023, the peak stands 1.88 metres higher, while it sits 1.29 metres lower than the figure for 2025. The bedrock beneath the ice lies at about 4,792 metres, and the summit height above it reflects the snow and ice cap resting on the rock. Because that cap keeps changing, no single reading gives a fixed height.

How the summit was measured

Teams of surveyors, mountain guides and scientists reached the highest point on the border between France and Italy on 17 September. Satellite technology located the exact peak, and almost 30 kilograms of extra measuring equipment went up with the team. Over more than two hours, the crew measured the snow and ice cap covering the rock. A drone captured 1,300 images to build a three-dimensional model of that cap, and ground-penetrating radar mapped the ice layer and the rock below it. The measurements have been taken since 2001, typically every two to three years, so that the results can be analysed as a series over time.

Why the height keeps changing

The summit height depends on the thickness of the snow and ice on top, which in turn depends on wind, precipitation, temperature, sunshine and how the snow is moved and redistributed. Mathieu Dragon, a licensed surveyor from Haute-Savoie, said wind and precipitation are shaping the peak, even though this year was unusually dry. Jean des Garets, who leads the Haute-Savoie chamber and the expedition, said the summit is constantly in motion and that single measurements say little about climate warming. Popular memory rounds the height to 4,810 metres, and des Garets said that rounding to the nearest ten is not unreasonable given swings of several metres from year to year.

The Union Nationale des Géomètres-Experts, whose surveyors have monitored the peak since 2001, stressed the gap between surface height and ice volume. A spokesperson put it this way:

Regarding ice mass, it is essential to distinguish between changes in surface altitude and changes in the total volume or mass of ice.

The spokesperson added that a higher summit does not necessarily mean the mountain has gained ice, and that the reading does not contradict the documented retreat of Alpine glaciers.

Earlier readings and the 2007 peak

Readings over the past decades have moved up and down. Several measurements between 2000 and 2010 came in around 4,810 metres. The height fell to 4,807.81 metres in 2021 and then to 4,805.59 metres in 2023, when the mountain was at its lowest level in recent memory. The highest reading in the record, 4,810.90 metres, dates from 2007, and the summit now sits 3.43 metres below it.

Climate context and cautions

Experts warned against reading year-to-year height changes as evidence about the rapid loss of Alpine ice, which they linked to fossil fuel pollution. This year's summer was the hottest on record in western Europe, and climate change was one factor. In early October 2026, Swiss glaciologists warned that melting was accelerating sharply after confirming that one-fifth of the country's ice had been lost over the past five years, with 5.5% of volume lost between 2025 and 2026. Whether Mont Blanc counts as Europe's highest mountain depends on where the border between Europe and Asia is drawn. If the Caucasus is counted as part of Europe, the Elbrus, at 5,642 metres, is the continent's highest peak, while Mont Blanc remains the highest in western Europe.