Mercator distortion explorer

Choose a reference latitude

Results update instantly. Use the button only if you want a shareable URL.

Reference input

Use a city Use a custom latitude Drop a pin on the map

City

GeoNames-derived city set with 6077 entries. Pick a place people actually recognize, then see how much Mercator enlarges it.

The highlighted city becomes the shareable URL reference.

Custom latitude

Useful when you want to test an arbitrary latitude band instead of a named place.

Map pin

Pinned location 64.1814°, -51.6941°

Latitude

Longitude

The pin is useful when the map-reading question is about a region, sea route, or arbitrary spot rather than a city.

Map base: World map configurable.svg on Wikimedia Commons, a CC0 Robinson projection centered at 10°E.

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What this page answers

A lot of pages say Mercator is distorted, but stop before quantifying it. This page answers the follow-up: how distorted is this latitude, in numbers a normal reader can actually use?

It focuses on the classic search problem behind Greenland-style map arguments: Mercator preserves local shape, but it expands local scale by the secant of latitude, so high-latitude places get drawn far too large in area.

The page now separates two questions people often mix together: what happens to a same-size real-world patch, and what happens to a 1° by 1° latitude/longitude grid cell. Those are not the same object.

It also answers the common follow-up directly: Mercator row heights are not constant on the map. Each 1° latitude band gets farther apart as you move poleward.

Useful search intents: Mercator distortion, why Greenland looks so big, map scale by latitude, and Mercator area exaggeration.

Good for

• Explaining why web maps make high-latitude regions feel misleadingly large
• Teaching the difference between local shape preservation and area truth
• Checking how severe Mercator exaggeration is for a city, route, or arbitrary latitude

Important limitation

This page explains Mercator's latitude-driven distortion only. It does not compare every projection family or claim that Mercator is useless; it just makes the main distortion legible.

If you are thinking in terms of latitude/longitude grid cells: a 1° cell gets narrower on Earth as latitude rises, while Mercator also spaces the parallels farther apart on the map. Mercator row heights are not constant. That map-side y stretch happens for the same reason as the x stretch: Mercator keeps local scale equal in both directions so small shapes keep their angles.

Read the follow-up note about Mercator row heights.