# The True Size of Africa: Why Mercator Shrinks a Continent

Africa is about 14 times the size of Greenland, but a Mercator map draws them nearly equal. Here is the arithmetic behind the distortion, and why a UN resolution ended up being about it.

> Editor: https://ohmymaps.com/ · Versão em página: https://ohmymaps.com/blog/true-size-of-africa-mercator/

Put a Mercator world map on a wall and ask someone to compare Greenland with
Africa. Most people will say they look about the same, because on that map they
do.

Africa covers roughly 30.4 million square kilometres. Greenland covers roughly
2.2 million. Africa is about **fourteen times larger**. Greenland is about 7% of
Africa, which is the same fact stated the other way round and is worth
remembering because both numbers circulate.

<figure>

![World map on Mercator with Greenland shaded orange and every African country shaded yellow, the two landmasses looking comparable in size](/blog/posts/africa-greenland-mercator.svg)

![The same two landmasses on Equal Earth, where Greenland shrinks to a sliver beside Africa](/blog/posts/africa-greenland-equal-earth.svg)

<figcaption>The same selection, two projections. On Mercator, Greenland rivals a continent. On Equal Earth, it is about 7% of it.</figcaption>

</figure>

This gap is why the UN General Assembly
[adopted a resolution about map projections](/blog/un-equal-earth-map-resolution/)
in September 2026, and it is the whole substance of the Correct the Map campaign
that the African Union backed a year earlier.

## Where the distortion comes from

Mercator is a **conformal** projection: it preserves angles and local shape. That
is not a side effect, it is the entire design goal. Gerardus Mercator published
it in 1569 so that a navigator could draw a straight line between two ports and
sail a single constant compass bearing along it. No other projection makes that
as easy, which is why it is still the basis of marine and air charts and of the
tiles in most web map apps.

Preserving angle costs area, and the price is not spread evenly. To keep shapes
locally correct as the meridians are forced apart into parallel vertical lines,
the map has to stretch vertically by the same factor it stretched horizontally.
That factor grows as you move away from the equator, and it grows fast.

The consequences run in one direction:

- **Near the equator**, almost no inflation. Africa straddles the equator, so
  Africa is drawn close to its honest relative size. It is not shrunk. Everything
  else is grown.
- **At middle latitudes**, noticeable inflation. Europe and the United States
  gain substantially.
- **Near the poles**, extreme inflation. Greenland, northern Canada, Russia and
  Scandinavia balloon.
- **At the poles themselves**, infinity. This is why Antarctica cannot be drawn
  on a true Mercator at all, and why web maps crop somewhere around 85 degrees.

So the familiar claim that "Mercator makes Africa look small" is slightly off
target, and the more precise version is more damning. Mercator draws Africa
about right and inflates the temperate and polar world around it. The continent
does not shrink. It is crowded out.

## Why this stopped being only a cartography argument

A projection is a technical choice, but the maps built on it are not only
technical objects. The map on a classroom wall is, for a lot of people, the only
picture of the world they will ever study closely, and it is doing work on their
sense of proportion the entire time.

That is the argument Togo made when it tabled the resolution on behalf of the
African Group, and the text described the correction in terms of cognitive
justice. You can find that framing overstated and still concede the mechanical
point underneath it, which is that a great many general-purpose maps use a
navigation projection for no reason other than inheritance, and pay for it with
a systematic distortion that runs the same way every time.

## What the fix is not

Two clarifications, because both got mangled in the coverage.

**Nobody is proposing to retire Mercator.** The UN text explicitly preserves it
for marine and air navigation. A rhumb line is still a rhumb line, and no
equal-area projection will give you one.

**Equal-area does not mean undistorted.** There is no undistorted flat map. An
equal-area projection buys exact area by spending the error on shape, so on
Equal Earth, Greenland is the right size but the wrong shape. That is a better
trade for a thematic map and a worse one for a chart you plan to navigate by.
The choice is between errors, never between error and truth.

## The honest way to check

The fastest way to stop taking anyone's word for this, including ours, is to
paint the two landmasses on a map and flip the projection under them.

Colour Greenland and every country in Africa, then switch from Mercator to Equal
Earth. Nothing about your data changes. The countries you selected stay
selected, the colours stay put, and the only thing that moves is the amount of
the frame each one occupies. Watching that happen in one click does more than
any number in a paragraph.

<div class="cta">
  <p><strong>Run the comparison.</strong> Paint Greenland and Africa, then flip between Mercator and Equal Earth and watch the fourteen-to-one appear.</p>
  <a class="cta-button" href="https://ohmymaps.com/">Open the editor</a>
</div>

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Related reading:
[What is the Equal Earth projection?](/blog/equal-earth-projection-explained/)
and
[How to make an Equal Earth map online](/blog/make-an-equal-earth-map-online/).