Key facts
- Data: Terrain Tiles (USGS 3DEP, SRTM and other models) for the ground height, usually within 5–10 m and 1–2 m where lidar exists; EGM96 geoid (NGA) to turn a phone's GPS height above the ellipsoid into height above sea level.
- Runs in your browser: what you click, draw or open is not uploaded.
- Data and libraries: OpenFreeMap, MapLibre GL JS, Terrain Tiles (Mapzen / Tilezen on AWS Open Data), EGM96 geoid model (NGA), GeoNames (via all-the-cities), GeoNames postal codes (via zipcodes-us), IANA time zone database (tz database), in your browser.
- Free to use, with no sign-up and nothing to install.
"How high am I right now?" is a question for hikers checking a map, cyclists after a climb, people reading a recipe that changes above 1,000 m, gardeners choosing plants, buyers of a house near the coast, and anyone whose phone shows a strange altitude. This page answers it in two ways and shows both. The first is the ground height at your position, read from an open elevation model built from lidar, radar and survey data; that is the number a topographic map would give. The second is the altitude your phone or tablet works out from GPS satellites, which many people see in a compass or fitness app. The two rarely agree. Most devices give the GPS height above the WGS84 ellipsoid, a smooth mathematical shape that lies up to 106 m below and 85 m above the real sea level, and GPS is far less precise up and down than sideways. The page knows the size of that gap everywhere on Earth from the EGM96 geoid model, converts the GPS reading to height above sea level and tells you which number to trust. Before you share anything, it shows the elevation of the town that matches your browser's time zone, so there is an answer the moment the page opens; your position is only requested when you press the button, and it is never sent to GeoDrafter.
How to use it
- Open the page – the elevation of the town of your time zone is shown at once, in metres and feet.
- Press "Find my elevation" and allow your browser to share your position.
- Read the ground height where you are, your device's GPS altitude and what the difference means.
- If the dot is not where you are, click your exact spot on the map, or search a town or postcode; copy the link or download the points as CSV.
How accurate is it?
How exact the ground height is
The ground height comes from the Terrain Tiles dataset, read at its finest level of about 3–5 m per pixel. Where a lidar survey is behind it – most of the United States, the United Kingdom, much of western Europe, Australia and New Zealand – it is usually within one or two metres of the truth. Elsewhere it rests on the SRTM radar survey, typically within 5–10 m and worse on cliffs and steep slopes. It is the height of the ground: on the fifth floor of a building you are about 15 m higher than the number shown.
Why your phone's altitude is different
GPS fixes the height from the same satellites as the position, but all of them are above you, so the vertical error is about one and a half to three times the horizontal error: 10–30 m is common, more indoors and between tall buildings. The Geolocation standard says browsers report height above the WGS84 ellipsoid; some phones correct it to sea level first. The page compares the reading with the ground height both ways and says which one fits, and the altitude accuracy your device reports is shown next to it.
From ellipsoid to sea level
The difference between the ellipsoid and sea level is called the geoid undulation. The page takes it from EGM96, the geoid model published by the US National Geospatial-Intelligence Agency that GPS receivers use themselves, sampled on a one-degree grid. That grid is within 2 m of the full model for 99 % of the world. In Denmark sea level is about 36–42 m above the ellipsoid, in Colorado about 17 m below, and south of India nearly 100 m below.
Good to know
A laptop does not know where it is
Computers without GPS place themselves from nearby Wi-Fi networks or the internet address, which can be hundreds of metres or several kilometres off. The page shows the accuracy your browser reports and warns when it is worse than 200 m; then click your exact spot on the map, because the height of the wrong hillside is no answer at all.
The town guess is not your position
The first answer is for the largest town whose name matches your time zone – Copenhagen for Europe/Copenhagen, Denver for America/Denver – not for where you are. People in Aarhus or Colorado Springs see Copenhagen or Denver until they press the button or search their own town, and the page says so under the result.
Barometric altimeters drift
Watches and some phones measure height from air pressure. They follow climbs well but drift with the weather by tens of metres in a day unless they are set to a known height. Use the ground height shown here as that known height at a trail head or summit.
Frequently asked questions
What is my elevation right now?
Press "Find my elevation" and allow your browser to share your position. The page shows the ground height where you are in metres and feet, the accuracy of the position and, on a phone, the altitude from its GPS. If the dot is in the wrong place, click your spot on the map.
Why does my phone show a different altitude?
Most phones give the GPS height above the WGS84 ellipsoid rather than above sea level, and GPS heights are often 10–30 m off. The page converts the reading with the EGM96 geoid model and shows how far it is from the ground height, so you can see which part of the gap is the ellipsoid and which is GPS error.
How accurate is the elevation?
Within about 1–2 m where the elevation model comes from lidar, as in most of the United States and much of Europe, and typically 5–10 m elsewhere. The position matters as much: on a laptop it can be hundreds of metres off, so check the dot on the map.
Can I find my elevation without sharing my location?
Yes. Search your town or postcode, paste coordinates, or click your spot on the map. The page also opens with the town of your time zone, which is guessed from your browser's settings and needs no permission.
How do I find the elevation of my house?
Search your town, zoom in and click your house on the map; the panel shows the ground height there. The search knows towns and, in some countries, postcodes, but not street addresses. For a whole route use the elevation profile, and for many points the elevation finder.
Something wrong or missing? E-mail [email protected] and it will be fixed.