What Percentage of the Earth’s Surface Is Land?

About 29 percent of Earth’s surface is land, with the remaining 71 percent covered by ocean and other bodies of water. In absolute terms, that works out to roughly 149 million square kilometers of land spread across a total surface area of around 510 million square kilometers. The split sounds simple enough, but the way that land is distributed, how we measure it, and how the ratio is shifting over time all raise questions that make the figure more interesting than it first appears.

Where the 29 Percent Comes From

Earth’s surface area can be calculated from its radius with basic geometry, and modern satellite geodesy has refined that number to a high degree of precision. The total comes to approximately 510.1 million square kilometers. Of that, the oceans and seas account for about 361 million square kilometers, leaving around 149 million square kilometers of land. The exact percentages vary slightly depending on what you count as “land” versus “water” at the margins, but the consensus figure used by geographers and space agencies alike is roughly 29.2 percent land and 70.8 percent water.

Those numbers refer to the present-day configuration of continents, ice sheets, and sea level. They are not permanent. Over geological timescales, plate tectonics has rearranged the continents entirely, and even over the past twenty thousand years, changes in sea level have meaningfully altered how much land sits above water.

Land Is Not Spread Evenly

One of the more striking features of Earth’s geography is how unevenly land is concentrated between the two hemispheres. The Northern Hemisphere holds the vast majority of Earth’s landmass. Roughly two-thirds of all land sits north of the equator, including nearly all of Europe, most of Asia, most of North America, and the northern portions of Africa and South America. The Southern Hemisphere, by contrast, is overwhelmingly ocean, with Antarctica, Australia, and the southern parts of Africa and South America making up a much smaller share of total land.

This asymmetry has real consequences for climate. Because water heats and cools more slowly than land, the Southern Hemisphere experiences a narrower range of seasonal temperature swings at comparable latitudes. In the Northern Hemisphere, those moderate temperature ranges are found only in limited open-ocean areas, while continental interiors swing dramatically between summer and winter extremes.¹ The upshot is that two cities at the same latitude but in different hemispheres can have wildly different climates, largely because of how much land surrounds them.

There is also a longitudinal pattern. If you spin a globe and look at the Pacific Ocean from the right angle, you can find a view where nearly an entire hemisphere appears to be water, with barely any land visible. This “water hemisphere,” centered roughly on New Zealand, is an arresting reminder of just how dominant the ocean is. The opposite “land hemisphere,” centered near France, contains the bulk of Earth’s continents but is still more water than land.

What Counts as Land

The 29 percent figure includes everything above sea level, whether or not anyone could live there. That means Antarctica’s 14 million square kilometers of ice-covered rock count as land, as does Greenland’s ice sheet. Together, those two ice masses account for roughly 10 percent of Earth’s total land area. If both were to melt entirely, they would not disappear from the land tally immediately, since bedrock lies beneath the ice, but the resulting sea level rise (on the order of 60-plus meters if every last glacier melted) would drown enormous stretches of coastal land elsewhere, changing the overall percentage significantly.

Inland water bodies also complicate the picture. Lakes, rivers, reservoirs, and wetlands sit on what is geologically “land” but are clearly water on the surface. The world’s largest lakes alone cover hundreds of thousands of square kilometers. Whether you include or exclude these features shifts the land percentage by a small but real amount. Most standard figures treat the continental surface, including its freshwater bodies, as part of the 29 percent, with “ocean” referring specifically to the interconnected saltwater body.

Then there are tidal zones and seasonal fluctuations. Coastlines are not static lines. Tidal mudflats, mangrove swamps, and seasonally flooded plains shift between “land” and “water” depending on the time of day or year. Satellite-based measurements have to make decisions about when to capture imagery and how to classify these transitional zones, which introduces small but real variation in any land area estimate.

How the Ratio Has Changed Over Time

Earth’s land-to-water ratio has never been fixed. Over hundreds of millions of years, plate tectonics has assembled and broken apart supercontinents, opened and closed ocean basins, and built mountain ranges that altered drainage patterns. But you do not need to look back that far to find meaningful changes. During the last ice age, which peaked roughly 20,000 years ago, so much water was locked up in continental ice sheets that global sea level dropped about 120 meters below where it sits today. That exposed vast stretches of continental shelf, connecting landmasses that are now separated by water.

A study estimating habitable land area during that glacial maximum found that across Africa, Eurasia, and Australia alone, the available land totaled nearly 77 million square kilometers, substantially more than those same regions offer today.² The Bering land bridge between Siberia and Alaska, the exposed floor of the North Sea, and wide coastal plains off Southeast Asia were all dry ground at the time. When the ice melted and seas rose over the following millennia, those areas flooded, and the modern coastline took shape.

The reverse process is now underway, albeit on a much smaller scale so far. As the planet warms, thermal expansion of ocean water and melting ice are gradually raising sea levels. The change since 1900 has been on the order of 20 centimeters, which sounds modest but has already contributed to measurable land loss in low-lying areas.

Modern Land Loss at the Coasts

Coastal erosion and sea level rise are actively shrinking the land surface in many parts of the world. A global analysis of satellite imagery from 1984 to 2015 found that roughly 28,000 square kilometers of permanent land was lost in coastal areas during that period, an area about the size of Haiti. Over the same time frame, about 14,000 square kilometers of new land was gained through sediment deposition and other processes, leaving a net loss of around 14,000 square kilometers.³ In the global picture, 14,000 square kilometers is a tiny fraction of 149 million, but the losses are concentrated in places where people live, farm, and fish.

River deltas are especially vulnerable. These flat, low-lying landforms are home to hundreds of millions of people worldwide and are losing ground to a combination of sinking land (often accelerated by groundwater pumping), reduced sediment supply from dammed rivers, and rising seas. Under a high-emissions climate scenario, projections suggest that more than 85 percent of delta land loss by 2100 would be driven by climate-change-related sea level rise, resulting in the loss of roughly 5 percent of all global delta land.⁴

Some of the most dramatic examples are already visible. In coastal Louisiana, a region built on the Mississippi River delta, land has been converting to open water for decades due to subsidence, canal dredging, and storm damage. Modeling suggests that about 180 square kilometers of land in that region has a greater than 50 percent chance of becoming water between 2016 and 2031.⁵ On a country level, Colombia faces the potential loss of nearly 2,841 square kilometers of coastal area under a worst-case sea level rise scenario of about one meter.⁶ Neither of these numbers will shift the global 29 percent figure in a way you could see on a pie chart, but they represent enormous disruptions for the communities involved.

How Humans Have Reshaped the Land That Exists

The total area of land matters, but so does what that land looks like. Human activity has transformed a staggering share of Earth’s terrestrial surface. A landmark paper in the late 1990s estimated that between one-third and one-half of the land surface had been transformed by human action, including agriculture, urbanization, forestry, and infrastructure.⁷ More recent satellite-based assessments broadly confirm this picture while adding nuance.

A 2025 analysis of global terrestrial modification found that as of around 2022, about 43 percent of terrestrial lands had very low levels of human modification, while 27 percent showed low modification, 20 percent moderate modification, and 10 percent high modification.⁸ In other words, more than half of all land shows at least some measurable human footprint, and about 30 percent has been moderately to heavily altered. The least-modified areas tend to be in places humans find hard to use: the interior of the Amazon, the boreal forests of Siberia and Canada, the high-altitude Tibetan Plateau, and the ice sheets of Antarctica and Greenland.

Agriculture is by far the largest driver of transformation. Cropland and pasture together occupy roughly 40 percent of the world’s ice-free land surface, a share that has grown enormously over the past few centuries but has begun to stabilize in some regions as farming becomes more intensive. Urban areas, despite dominating the human experience, cover only a few percent of land globally, though their indirect effects on surrounding landscapes through resource demand and transportation networks extend much further.

Why Maps Mislead Us About Land Area

Most people develop their sense of how much land exists, and where it is, from maps. The problem is that flattening a sphere into a rectangle inevitably distorts something: area, shape, distance, or direction. The most familiar world map projection, the Mercator, preserves shapes and angles (useful for navigation) but dramatically inflates the apparent size of landmasses near the poles. Greenland ends up looking as large as Africa, when in reality Africa is about 14 times bigger.

Research on how map projections shape perception has found that people who rely on distorted reference maps can develop skewed mental models of geographic size, which may influence decision-making about global issues.⁹ This is not just a trivia-night curiosity. If your mental image of the world inflates high-latitude landmasses and shrinks equatorial ones, you might unconsciously misjudge where most of Earth’s habitable or arable land actually lies. Equal-area projections exist and are commonly used in atlases and geographic information systems, but the Mercator and its close relatives remain deeply embedded in popular culture through web mapping services and classroom posters.

The distortion also affects how people perceive the ocean. On a standard Mercator map, the ocean is visually compressed because the projection spreads land horizontally to fill the frame. On a globe, or on an equal-area projection, the sheer dominance of water becomes much more visceral. The Pacific Ocean alone is larger than all the land on Earth combined, a fact that maps rarely make intuitive.

How Earth Compares to Other Rocky Worlds

Earth is the only known planet with stable liquid water on its surface, which makes the land-to-water ratio a question unique to our world in the solar system as we currently observe it. Mars once had surface water but lost it. Venus may have had oceans billions of years ago. The other rocky planets and moons either lack atmospheres or are too hot or cold for liquid water at the surface.

But the question of what determines the land-to-water split on a rocky planet is increasingly relevant to the search for habitable worlds beyond our solar system. A 2025 review examined the physical conditions that set this ratio on temperate rocky planets, how it would affect climate and biological processes, and whether future telescopes might be able to constrain land-to-ocean ratios on exoplanets from afar.¹⁰ The balance depends on how much water a planet receives during formation, how much it retains over billions of years, and the depth and shape of its ocean basins, which are governed by plate tectonics or its absence.

Earth’s roughly 30/70 split is not inevitable for a habitable world. A planet with slightly less water could be mostly land with scattered seas. A planet with slightly more could be a true “water world” with no exposed continents at all. Both scenarios would produce radically different climates, weather patterns, and prospects for complex life. The interaction between land and ocean drives the carbon cycle, weathering of rocks, nutrient transport, and atmospheric chemistry in ways that a purely water-covered or purely land-covered world would handle very differently. Earth’s particular mix appears to be a sweet spot for the kind of geology and biology we observe, but whether that makes it rare or common among habitable planets is a question astronomers are only beginning to tackle.

The Surprising Amount of Uninhabitable Land

Knowing that 29 percent of Earth is land invites a follow-up: how much of that land can people actually use? The answer is less than you might expect. Roughly a third of all land is desert, including both hot deserts like the Sahara and cold deserts like interior Antarctica. Another large fraction is permanently ice-covered, extremely mountainous, or otherwise hostile to agriculture and settlement. By many estimates, only about a quarter to a third of Earth’s land surface is genuinely suitable for growing food, and a meaningful share of that is already in use.

This means the effective land area available for human habitation and food production is far smaller than the headline 149 million square kilometers suggests. When people talk about “running out of land,” they are not usually worried about the total quantity of dry ground on the planet. They are worried about the much smaller pool of fertile, accessible, well-watered land with a tolerable climate, and how that pool is being divided among farmland, cities, forests, and conservation areas. The 29 percent figure, in that context, is just the starting point for a much more granular and consequential set of questions about what Earth’s surface can actually support.