What Is My Elevation? Height Above Sea Level

Tap Use my location to see your elevation: the height of the ground where you stand, in feet and meters, read from a terrain model. Or type a place, an address or coordinates. Denver’s State Capitol reads 5,278 ft (1,609 m), where the air pressure is 82% of sea level’s.

How to use it

Tap Use my location and allow your browser to share it, or type a town, an address, a mountain or two coordinates (39.7392, -104.9849) and press Find. The answer is the ground’s height at that point; on a phone with GPS you also see the altitude your phone measured, with its own margin of error. Switch between feet and meters at the top. Your location is used for this one answer and stays out of the page’s address; Copy link puts the place in the link only when you ask it to.

Where the height comes from

The Terrain Tiles on AWS, a height model of the whole Earth built from government surveys: in the United States, the U.S. Geological Survey’s 3D Elevation Program; elsewhere SRTM, GMTED2010 and national models. It is the ground, not a survey marker: it rounds off sharp summits (Mount Everest’s reads 8,734 m here) and in some cities outside the U.S. it can read the tops of buildings and trees. A phone’s GPS altitude is a different measurement with its own error, which the phone reports; the two often differ by tens of feet.

What your elevation means

The air thins as you climb. NASA’s Earth Atmosphere Model: “In the troposphere, the temperature decreases linearly and the pressure decreases exponentially.” Its curve fit, with h in feet: “T = 59 – .00356 * h” and “p = 2116 * [(T + 459.7)/ 518.6]^5.256”. That is where the air-pressure share comes from.

For altitude sickness the height that matters is where you sleep. The CDC: “Avoid going directly from low altitude (1,200 m or <4,000 ft) to 2,750 m (>9,000 ft) sleeping altitude in one day.” And: “For example, acclimatizing for a minimum of 2–3 nights at around 2,450 to approximately 2,750 m (8,000–9,000 ft) before proceeding to a higher altitude is markedly protective against acute mountain sickness (AMS).” The Altitude Sickness Planner starts from your height.

Air pressure by elevation

NASA’s model at each height, as a share of the pressure at sea level.

Worked examples

Mexico City. The Zócalo reads 7,308 ft (2,228 m): air pressure 76% of sea level’s, below the CDC’s 2,450 m band.

La Paz, Bolivia. Plaza Murillo reads 11,972 ft (3,649 m), 64%: above 3,000 m, where the CDC’s pace applies.

Pikes Peak and Death Valley. The summit of Pikes Peak reads 14,093 ft (4,296 m); Badwater Basin −261 ft (−80 m), below sea level.

Common mistakes

• Taking the GPS number as exact. A phone’s altitude comes with a margin of error it reports; indoors or under trees it can be far off.
• Reading a summit from a terrain model. A model averages the ground over a few meters, so a sharp peak reads lower than its surveyed height.
• Planning by the highest point, not the bed. The CDC: “Hypoxemia is greatest during sleep; day trips to high-altitude destinations with an evening return to a lower altitude are much less stressful on the body.”
• Forgetting where you start. A trip from Denver starts at a mile high; from Miami, at sea level.

Plan the trip

Read Rocky Mountain National Park, things to do in Denver, Mexico City, Cusco and La Paz, Bolivia. Then plan the nights up high with the Altitude Sickness Planner, time a hike with the golden hour, and check the national park pass.