The Highest and Lowest Points on Earth: Everest, Challenger Deep, and the Full Vertical Range
Photo: Ann H / Pexels
On December 8, 2020, China and Nepal jointly announced that Mount Everest stands 8,848.86 meters (29,031.7 feet) above sea level — 86 centimeters taller than the figure that had been used since India's Survey of India established 8,848 meters in 1954. That extra 86 centimeters came from more precise gravity modeling and GPS measurements, not from the mountain growing. At the opposite extreme, a 2021 high-precision sonar survey confirmed that the floor of Challenger Deep in the Mariana Trench sits 10,935 ± 6 meters below sea level. Between these two points, Earth's surface spans a vertical range of nearly 19.8 kilometers — more than enough to stack two Mount Everests on top of each other with room to spare.
How "Height" and "Depth" Are Measured
Before comparing records, the measurement reference matters. Sea level sounds like a simple baseline, but it is not: the ocean is not flat. Gravity variations caused by differences in Earth's internal mass distribution mean the ocean surface bulges and dips slightly — by as much as 100 meters between different ocean regions. Scientists use the geoid as the reference surface: a mathematical model of where the ocean surface would sit if it extended under all the continents, shaped entirely by gravity and Earth's rotation.
Geoid — an equipotential surface of Earth's gravitational field, corresponding to mean sea level as if all the land were removed and the ocean could flow freely. Heights reported relative to the geoid are "orthometric heights" — what a surveyor's level instrument measures. GPS systems measure heights relative to a mathematical ellipsoid and require a geoid correction to give sea-level-referenced heights.
When the 2020 China-Nepal survey added 86 centimeters to Everest's official height, the correction came largely from improved geoid modeling over the Himalayas — the reference surface itself was recalibrated, not just the GPS measurement.
For ocean depth, the reference is the same sea level surface, and depth is measured by multibeam sonar: a hull-mounted array of transducers that emit sound pulses in a fan pattern across the seafloor, then record the time each pulse takes to return. The speed of sound in seawater depends on temperature, salinity, and pressure; these must be measured simultaneously for accurate depth conversion.
Source: Survey of Nepal / National Bureau of Surveying and Mapping of China (2020), official joint press release — establishing the current official height of Mount Everest at 8,848.86 m.
Source: NOAA (2021), "Mapping the Deep: The Mariana Trench" — NOAA technical summary of multibeam sonar methodology and Challenger Deep depth revision to 10,935 ± 6 m.
Mount Everest: The Highest Point Above Sea Level
Mount Everest stands in the Mahalangur Himal subrange of the Himalayas, on the border between Nepal and Tibet (China). Its Nepali name is Sagarmatha; in Tibetan, it is Chomolungma. The mountain was first identified as the world's highest by the Survey of India in 1852, when "Peak XV" calculations from stations in the Indian plains — correcting for atmospheric refraction and the curvature of the Earth — gave a height of exactly 29,000 feet. The precise value was revised to 29,002 feet (8,840 meters) to avoid the implausibly round figure appearing as an estimate.
The current official measurement of 8,848.86 m was established by teams from Nepal and China that spent the spring of 2019 and 2020 placing GPS receivers, gravity meters, and leveling instruments at summit and subsidiary stations across the Himalayas. The joint announcement on December 8, 2020 resolved a long-standing discrepancy between the Chinese official figure (8,844.43 m, measured from bedrock without the snow cap) and the Nepalese/international figure (8,848 m, measured to the snow surface).
Orthometric height — height above the geoid, the reference used for Mount Everest's official measurement. It answers the question: "How high above where sea level would be?"
Everest continues to grow, very slowly. The Indian subcontinent is still colliding with Eurasia at roughly 4.4 centimeters per year, and the Himalayas continue to rise as a result. The mountain also oscillates slightly: seismic events can change its elevation by centimeters. The 2015 Gorkha earthquake (M7.8) temporarily reduced Everest's elevation by approximately 2.5 centimeters as the surrounding crust shifted.
| Peak | Height (m) | Location | Notes |
|---|---|---|---|
| Everest (Sagarmatha/Chomolungma) | 8,848.86 | Nepal/China border | Highest above sea level |
| K2 (Chhogori) | 8,611 | Pakistan/China border | Second highest; most technical |
| Kangchenjunga | 8,586 | Nepal/India border | Third highest |
| Lhotse | 8,516 | Nepal/China border | Fourth highest; south face is world's biggest |
| Makalu | 8,485 | Nepal/China border | Fifth highest; pyramid-shaped |
| Cho Oyu | 8,188 | Nepal/China border | Sixth; most climbed 8000-er |
| Mauna Kea (from seafloor) | 10,211 | Hawaii, USA | Tallest from base; only 4,205 m above sea level |
Source: Survey of Nepal (2020), official technical report — GPS, gravity, and snow-ice survey methodology for the 8,848.86 m determination.
Source: NASA (2015), "Nepal Earthquake Analysis" — documentation of the 2–3 cm coseismic height change of Everest during the Gorkha earthquake.
The Tallest Mountain on Earth (If You Measure Differently)
Everest is the highest point above sea level. But the tallest mountain on Earth — measured from base to summit — is Mauna Kea in Hawaii. The volcano rises approximately 10,211 meters from its base on the Pacific Ocean floor to its summit, which sits 4,205 meters above sea level. Most of the mountain is submerged.
A third competitor exists for "farthest from Earth's center": Mount Chimborazo in Ecuador, at 6,263 meters above sea level, sits near the equatorial bulge — Earth's equatorial radius is about 21 km greater than its polar radius due to rotation. Chimborazo's summit is approximately 6,384 kilometers from Earth's center, compared to Everest's approximately 6,382 kilometers. For someone standing at the summit of Chimborazo, the ground beneath their feet is farther from Earth's center than the ground beneath a climber on Everest's summit.
Oblate spheroid — the shape of Earth, which is not a perfect sphere but is slightly flattened at the poles and bulging at the equator. The equatorial radius is 6,378.1 km and the polar radius is 6,356.8 km, a difference of about 21.3 km.
Source: USGS (2024), "The Highest Point on Earth" — factual summary distinguishing altitude above sea level (Everest), height from base (Mauna Kea), and distance from Earth's center (Chimborazo).
The Dead Sea: The Lowest Exposed Land Surface
The shore of the Dead Sea, on the border between Israel, the West Bank, and Jordan, is the lowest dry-land surface accessible to humans. The water level has been falling for decades due to diversion of the Jordan River for irrigation; from approximately 395 meters below sea level in 1970, it fell to around 430 meters below sea level by the early 2020s, declining at roughly 1 meter per year.
The Dead Sea is not technically a sea but a landlocked hypersaline lake — the salinity of its water runs approximately 34%, nearly ten times the salinity of the ocean. Water flows in from the Jordan River and smaller streams; nothing flows out. Under the desert sun, water evaporates rapidly, concentrating the dissolved minerals. The result is water so dense that swimmers float effortlessly without effort, and the absence of aquatic life that gives the lake its name.
Hypersaline lake — a landlocked body of water whose salinity exceeds that of seawater (approximately 3.5%). The Dead Sea's salinity fluctuates around 30–34%, making it one of the world's saltiest large bodies of water. Only halophilic (salt-loving) microorganisms can survive in it.
The lake's shore sits in the Jordan Rift Valley, part of the Dead Sea Transform fault system — a left-lateral strike-slip fault boundary between the African and Arabian tectonic plates. The valley is a geological trough that has been sinking as the two plates move past each other. The combination of tectonic subsidence and evaporative concentration has created one of the most geologically and chemically unusual environments on Earth.
Source: Gavrieli, I. and Oren, A. (2004), "The Dead Sea as a dying lake," in Dying and Dead Seas: Climatic versus Anthropic Causes, Springer — scientific analysis of the Dead Sea's declining water level and its causes.
Challenger Deep: The Deepest Point in the Ocean
Challenger Deep is a slot-shaped valley in the southern end of the Mariana Trench, in the western Pacific Ocean. It was first sounded by HMS Challenger in 1875, using a hemp rope with a weight on the end; the crew measured a depth of 8,184 meters. The current figure of 10,935 ± 6 meters comes from a 2021 high-resolution multibeam sonar survey, which is the most precise measurement to date.
The Mariana Trench forms where the Pacific Plate subducts beneath the Mariana Plate. Subduction zones create the deepest oceanic trenches because the oceanic plate bends downward as it sinks into the mantle. The Pacific Plate at this location is among the oldest oceanic crust on Earth — roughly 170 million years old — and because older oceanic crust is denser and thicker than younger crust, it subducts at a steeper angle and to greater depths.
Subduction zone — a convergent plate boundary where one tectonic plate slides beneath another and sinks into the mantle. The downgoing plate creates a trench at the surface and generates earthquakes and volcanoes as it descends. The Mariana Trench is the deepest subduction feature on Earth.
At 10,935 meters depth, the water pressure at Challenger Deep is approximately 1,086 times atmospheric pressure — equivalent to 1,086 bar, or about 108.6 megapascals. Under that pressure, water is slightly compressed: the density of seawater at Challenger Deep is about 5% higher than at the surface. The pressure would crush an unprotected human body instantly; specialized submersibles require pressure hulls of titanium or ceramic composite several centimeters thick.
Life nevertheless exists at Challenger Deep. Single-celled foraminifera, amphipod crustaceans, nematode worms, and microbial communities have all been found in sediment samples. The organisms survive through chemosynthesis (using chemical energy rather than sunlight) or by consuming organic matter that drifts down from the sunlit upper ocean — known as marine snow.
| Depth Point | Depth Below Sea Level | Location | Notes |
|---|---|---|---|
| Challenger Deep | 10,935 ± 6 m | Mariana Trench, Pacific | Deepest point in the ocean |
| Horizon Deep (Tonga Trench) | ~10,800 m | Tonga Trench, Pacific | Second deepest; some surveys give similar values |
| Sirena Deep (Mariana Trench) | ~10,700 m | Near Challenger Deep | Third deepest |
| Puerto Rico Trench (deepest Atlantic point) | ~8,400 m | Atlantic | Deepest point in the Atlantic |
| Java Trench (deepest Indian Ocean point) | ~7,450 m | Indian Ocean | Deepest in Indian Ocean |
| Dead Sea shore | ~430 m | Jordan Rift Valley | Deepest exposed land surface |
Source: Gardner, J.V. et al. (2014), "So, how deep is the Mariana Trench?," Marine Geodesy, Vol. 37 — analysis of depth measurement methodologies and uncertainty in the Mariana Trench; updated by the 2021 NOAA survey revising to 10,935 m.
The Denman Glacier Trough: The Deepest Land Point on Earth
The least famous of Earth's vertical records is also the most consequential for the future. Hidden beneath 2.7 kilometers of ice in East Antarctica, the Denman Glacier trough plunges to 3,500 meters below sea level — the deepest canyon on any continent, buried entirely under the Antarctic ice sheet.
The canyon was mapped by the BedMachine Antarctica project, led by Mathieu Morlighem of the University of California Irvine, which published its results in 2019. The project combined over a million measurements from satellites, aircraft, and ground-based radar to produce the most detailed map of the Antarctic bedrock topography ever assembled.
Ice-penetrating radar — an airborne or ground-based instrument that emits radar pulses downward through ice, which is largely transparent to radar frequencies. The pulse reflects off the bedrock beneath and returns to the receiver; the travel time gives the ice thickness and therefore the bedrock elevation. Multiple passes build a three-dimensional picture of what lies below the ice.
The Denman Glacier is an outlet glacier that drains a substantial fraction of East Antarctica's ice sheet toward the ocean. The trough it occupies slopes downward from the interior toward the coast — a geometry called a retrograde slope, where the bedrock is deeper further from the ocean. This configuration is inherently unstable for a marine ice sheet: if warm ocean water can access the grounding line (the point where the ice sheet meets the bedrock), it can melt the base of the ice, causing the grounding line to retreat inland and downslope, where deeper and deeper ice sits above more and more ocean water. Each retreat exposes more ice to ocean melting, creating a self-amplifying feedback.
NASA's Earth Observatory confirmed in 2019 that Denman Glacier has already lost approximately 268 billion metric tons of ice over the past 22 years and is retreating. The volume of ice above the Denman trough, if fully melted, would raise global sea level by approximately 1.5 meters on its own.
Source: Morlighem, M. et al. (2019), "Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet," Nature Geoscience, Vol. 13 — the BedMachine Antarctica paper establishing the Denman trough at 3,500 m below sea level.
Source: NASA Earth Observatory (2019), "Denman Glacier Losing Some of Its Footing" — NASA analysis of Denman Glacier mass loss and retreat rates from satellite altimetry.
Earth's Full Vertical Range
Adding these records together: from the summit of Everest at +8,848.86 meters to the floor of Challenger Deep at −10,935 meters, the total vertical range of Earth's surface is approximately 19,783.86 meters — call it 19.8 kilometers. For comparison, the diameter of Earth is approximately 12,742 kilometers. The entire range of Earth's surface relief is less than 0.16% of the planet's diameter.
This puts Earth's surface in physical context: it is extremely smooth relative to its size. If you shrank Earth to the size of a billiard ball (diameter ~57 mm), the height difference between Everest and Challenger Deep would be about 0.09 mm — well within the allowable smoothness tolerance of an official billiard ball (0.127 mm). In other words, Earth's surface irregularities are smaller, in relative terms, than the bumps on a billiard ball.
Yet those 19.8 kilometers span conditions ranging from −60 °C and near-zero atmospheric pressure at Everest's summit to +2 °C and 1,086 atmospheres at Challenger Deep — conditions under which the physics of the gas phase does not even apply.
Source: Thurman, H.V. and Trujillo, A.P. (2004), Introductory Oceanography, Prentice Hall — standard reference for ocean depth distributions and comparison of ocean depths to Earth's diameter.
Why Earth Has Extreme Topography
Earth's vertical extremes are a product of plate tectonics operating over billions of years. The planet's interior heat drives convection in the mantle, which moves tectonic plates at speeds of a few centimeters per year. Where plates converge, crust crumples and thickens, building mountain ranges; where plates diverge, ocean floor is created; where dense ocean plates subduct beneath lighter continental or ocean plates, the deepest trenches form.
Without plate tectonics, Earth would be a smoother planet. Mars, which lacks active plate tectonics, has a higher single mountain (Olympus Mons, 21.9 km above the Martian datum) but a smaller global range, because without plate recycling the crust equilibrates over time. Earth's ongoing plate activity continuously renews the topographic extremes — Everest keeps growing as India pushes into Asia; the Mariana Trench stays deep as the Pacific Plate keeps subducting.
The other factor is erosion. Rivers and glaciers work constantly to erode mountains and fill basins. The fact that Everest reaches 8.85 km reflects the balance between the rate of crustal thickening from the India-Eurasia collision and the rate of erosion by glaciers and rivers on the Himalayan flanks.
Source: Molnar, P. and England, P. (1990), "Late Cenozoic uplift of mountain ranges and global climate change: chicken or egg?," Nature, Vol. 346 — foundational analysis of the relationship between tectonic uplift, erosion, and the maintenance of extreme topography.
Frequently Asked Questions
Q: Is Everest really the tallest mountain on Earth?
A: It depends on how you define "tallest." Everest is the highest above sea level at 8,848.86 m. Mauna Kea in Hawaii is the tallest from base to summit at approximately 10,211 m, but most of it is underwater. Mount Chimborazo in Ecuador has its summit farthest from Earth's center (~6,384 km) because it sits near the equatorial bulge. For the everyday meaning of highest mountain, Everest is correct; the other definitions are physically real but answer different questions.
Q: Why does the Dead Sea keep getting lower?
A: The Dead Sea sits in a tectonic trough (the Jordan Rift Valley) and has no outlet — water only leaves by evaporation. The Jordan River, which historically provided 1.3 billion cubic meters of freshwater per year to the lake, has been reduced to a trickle by upstream diversions for agriculture in Israel, Jordan, and the Palestinian territories. With less inflow and the same evaporation rate, the lake level falls by roughly 1 meter per year. The drop also accelerates as the lake shrinks: a smaller surface area means less evaporation, but the lake chemistry also changes, affecting the evaporation rate.
Q: What is the pressure at Challenger Deep?
A: Approximately 1,086 atmospheres, or about 108.6 megapascals. For comparison, the pressure at sea level is 1 atmosphere (101,325 Pa). The pressure increases by roughly 1 atmosphere for every 10 meters of depth in the ocean; at 10,935 meters, it is about 1,093 times sea-level pressure. This is roughly the force of a 1-kilogram weight pressing on every square millimeter of surface — an unprotected human body would be instantly and completely crushed.
Q: Has anyone been to the bottom of Challenger Deep?
A: Yes, multiple times. Jacques Piccard and Don Walsh first descended in the bathyscaphe Trieste in January 1960, reaching a depth of approximately 10,916 m. James Cameron made a solo descent in the Deepsea Challenger submersible in March 2012. The Five Deeps Expedition conducted multiple crewed dives in 2019, including a dive by explorer Victor Vescovo that set the record at the time of approximately 10,928 m. The 2022 dive with Vescovo and Dawn Wright reached approximately 10,909 m at a different location.
Q: What is the Denman Glacier and why does it matter for sea level?
A: The Denman Glacier is an outlet glacier in East Antarctica that drains ice from the interior of the continent to the ocean. It sits above the deepest land canyon on Earth — 3,500 m below sea level — which is shaped in a retrograde configuration: deeper inland than at the coast. This geometry makes it vulnerable to marine ice sheet instability, a self-amplifying process where ocean water can progressively melt deeper and deeper ice without any further external forcing. If the Denman trough's ice sheet fully collapsed, it would raise global sea level by approximately 1.5 m.
Q: What is Earth's total vertical range?
A: From the summit of Everest (+8,848.86 m) to the floor of Challenger Deep (−10,935 m), Earth's surface vertical range is approximately 19,784 meters — about 19.8 km. Despite this seemingly large number, it represents less than 0.16% of Earth's diameter (12,742 km). Proportionally, Earth is smoother than a billiard ball; the allowable surface variation on an official billiard ball is 0.127 mm relative to a 57 mm diameter (about 0.22%), while Earth's topographic variation relative to its diameter is about 0.16%.
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SciHub101 is an independent science and technology publication founded and edited by Buğra Sözeri, a software engineer and app developer based in Türkiye. AI tools assist with drafting and research. Source documentation in the existing archive is uneven, and articles are being reviewed and corrected. The Editorial Team byline identifies editorial responsibility; it does not certify specialist or independent human review. Where we compare products, anything built by our own team is labelled as such — see the editorial guidelines and About page for how corrections and disclosures work.
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