How many people live in Nigeria?

How to get close to this number

Use the ratio in the explanation: about five times Spain, in twice the land area. Anchoring an unfamiliar country against a familiar one, with both a population and an area multiplier, gives you the figure and the density at the same time — and density is what makes the projection comprehensible.

This is the most populous country on its continent by a wide margin, holding a substantial share of the African total from the continent question on this site. Continental population growth is not evenly distributed; it is concentrated in a handful of countries, and this is the largest of them.

The projection is the part with global consequences: third most populous country in the world before mid-century. That reordering of the world's largest countries is one of the most consequential demographic shifts under way, and it is almost entirely absent from how most people picture the future global order.