How many people live in Mexico?

How to get close to this number

The explanation gives you the anchor directly: nearly three times Spain. If you know one Spanish-speaking country's population, the multiplier does the rest — and that relationship is the more memorable fact, because ratios between countries change far more slowly than absolute populations do.

The superlative is what most people get wrong. This is the most populous Spanish-speaking country in the world, comfortably ahead of the country the language is named after. Language communities and their nominal homelands are frequently mismatched in size, and this is the largest such mismatch in any major world language.

The internal concentration is the other structural fact: roughly one in five people live in a single metropolitan area. That degree of primacy shapes everything from national politics to internal migration, and it puts this country in the same structural category as Argentina rather than as a country with several comparable cities.