MPG stands for miles per gallon, a measurement of how far a vehicle can travel on one gallon of fuel. If a car gets 30 mpg, it can drive 30 miles before using up a gallon of gas.

This number matters because it tells you how fuel-efficient a vehicle is. A car that gets 40 mpg uses less gas than one that gets 20 mpg to cover the same distance. That means fewer stops at gas stations and less money spent on fuel. A hybrid car might get 50 mpg, while a large truck might only get 15 mpg because it's heavier and needs more power to move.

When families shop for cars, mpg is often an important factor in their decision. Higher mpg saves money over time and reduces the amount of fuel burned. Engineers work hard to design more efficient engines that squeeze more miles out of every gallon.

You might hear people say a car “gets good gas mileage” or has “great fuel economy.” Both phrases mean the same thing as having a high mpg rating. In countries that use the metric system, fuel efficiency is measured differently, in liters per 100 kilometers (L/100 km), but the concept is the same: how much fuel does it take to go a certain distance?