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Web Mercator Converter (EPSG:4326 ↔ 3857)

Convert WGS84 latitude and longitude to Web Mercator metres and back, with the scale and area distortion at that latitude worked out for you.

-14226.631
X (metres)
6711542.476
Y (metres)

EPSG:3857 coordinate

-14226.6309, 6711542.4756

Scale distortion (1 / cos φ)
1.6066×
Area distortion (1 / cos² φ)
2.5813×
Fraction of the world width
49.9645% from the west edge
Fraction of the world height
33.2526% from the north edge

A 1 km ruler laid on the map at this latitude covers 1.607 km of projected distance. Web Mercator preserves shape locally but never area.

How much Web Mercator stretches, by latitude

LatitudeY (metres)Length scaleArea scale
0°-01.00×1.00×
15°1,689,2001.04×1.07×
30°3,503,5501.15×1.33×
45°5,621,5211.41×2.00×
60°8,399,7382.00×4.00×
70°11,068,7162.92×8.55×
80°15,538,7115.76×33.16×
85°19,971,86911.47×131.65×

At 60° north a shape is drawn twice as wide as it is at the equator, and four times as large in area — which is why Greenland looks bigger than Africa on a web map.

What is the Web Mercator Converter (EPSG:4326 ↔ 3857)?

This converter moves coordinates between EPSG:4326 (plain latitude and longitude in degrees) and EPSG:3857, the Web Mercator projection every web map is drawn in.

  • Two-way conversion between EPSG:4326 degrees and EPSG:3857 metres
  • Reports the 1/cos φ length scale and 1/cos² φ area scale at your latitude
  • Clamps latitude to ±85.0511° and tells you when it has done so
  • Shows the position as a percentage across the projected world extent
  • Built-in distortion table from the equator to 85° for quick reference
  • Entirely client-side — coordinates never leave your browser

How to use the Web Mercator Converter (EPSG:4326 ↔ 3857)

  1. 1

    Choose whether you are converting degrees to metres or metres back to degrees.

  2. 2

    Enter latitude and longitude in decimal degrees or DMS, or paste the X and Y values in metres.

  3. 3

    Read the projected coordinate along with the scale and area distortion at that latitude.

  4. 4

    Copy the pair, and check the distortion table to see how much the projection stretches further north.

About the Web Mercator Converter (EPSG:4326 ↔ 3857)

This converter moves coordinates between EPSG:4326 (plain latitude and longitude in degrees) and EPSG:3857, the Web Mercator projection every web map is drawn in. Going forward it uses x = R·λ and y = R·ln(tan(π/4 + φ/2)) with R = 6378137 m; coming back it applies the inverse Gudermannian, φ = 2·atan(e^(y/R)) − π/2.

It is the conversion you need when a GIS layer, a tile server or a PostGIS query wants metres instead of degrees. Because Mercator stretches towards the poles, the tool also reports the 1/cos φ length distortion and the 1/cos² φ area distortion at your latitude — the numbers that explain why Greenland looks the size of Africa.

Latitude is clamped to ±85.0511° because that is where the projected world becomes square and the maths runs to infinity at the poles. All of it happens locally in your browser; nothing is uploaded.

Frequently asked questions

What is the difference between EPSG:4326 and EPSG:3857?

EPSG:4326 is unprojected latitude and longitude in degrees on the WGS-84 ellipsoid. EPSG:3857 is Web Mercator, a flat projection measured in metres that Google, OpenStreetMap, Bing and Mapbox all render in. They describe the same places with completely different numbers.

Why does Web Mercator stop at 85 degrees?

The projection stretches latitude by 1/cos φ, which runs to infinity at the poles. Cutting off at 85.05112878° makes the projected world exactly square, so it divides neatly into square tiles. The poles simply are not on a web map.

Is Web Mercator accurate for measuring distance?

Not directly. A metre on the EPSG:3857 grid is only a real metre at the equator; at 60° north it represents about half a real metre. Divide a projected length by the scale factor this tool reports, or measure on the sphere with a great-circle calculator instead.

Why is EPSG:3857 sometimes called EPSG:900913?

900913 was an unofficial code coined as a leetspeak spelling of "google" before the projection had a real one. It was later standardised as EPSG:3857, and you may also see the retired codes 3785 and 102113 in older software. They all mean the same projection.

Does Web Mercator use a sphere or an ellipsoid?

It takes WGS-84 ellipsoidal latitude and longitude but projects them with spherical formulas using R = 6,378,137 m. That mismatch is deliberate and is why EPSG calls it a pseudo-Mercator; it can shift positions by a few hundred metres compared with a true ellipsoidal Mercator.

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