Mexico uses the metric system. It always has. Litres, kilometres, kilograms—standard units across the country. That’s in sharp contrast to the United States, where the imperial system still rules. This difference shows up clearly at the gas pump.
In Mexico, fuel is sold by the litre. In the U.S., it’s by the gallon. That alone makes cross-border price comparisons tricky. American drivers need to do the math: one gallon equals 3.785 litres. So when they see fuel in Mexico priced at, say, 24 pesos per litre, they have to multiply to compare it with their $3.90 per gallon back home.
Mexico officially adopted the metric system in the 1800s, following a global trend toward standardization. Unlike Canada, which transitioned from imperial in the 1970s, or the U.S., which never fully switched, Mexico built its infrastructure around metric from the beginning. That means no dual units, no conversions—just one consistent standard.
For locals, there’s no confusion—everything is in litres, kilometres per hour, and pesos. But for tourists or U.S. drivers near the border, it often requires a quick calculation in their head. Fuel economy, too, is measured differently: kilometres per litre in Mexico vs. miles per gallon in the U.S. That changes how drivers think about efficiency and cost.
So while the road may be seamless between the U.S. and Mexico, the measurements aren’t. One country runs on metric, the other on imperial—and at the gas pump, that difference is hard to miss.
