Vehicle Emissions Per Mile Calculator

Vehicle Emissions Per Mile Calculator

Fuel economy directly and predictably determines a gasoline vehicle's per-mile CO2 emissions, since burning gasoline releases a fixed, well-established amount of CO2 per gallon regardless of the vehicle burning it.

CO2 (g/mile) = (19.6 lbs CO2 per gallon / MPG) x 453.592 g/lb

Example

A vehicle getting 30 MPG:

CO2 = (19.6 / 30) x 453.592 ≈ 296.3 g CO2/mile

Why 19.6 Pounds Per Gallon?

This figure comes directly from the carbon content of gasoline itself (roughly 87% carbon by weight) combined with the stoichiometry of complete combustion converting that carbon fully to CO2 - it's essentially a fixed physical constant for gasoline combustion, which is exactly why fuel economy alone is such a reliable predictor of per-mile tailpipe emissions.

What's Not Included

This figure covers only tailpipe CO2 from fuel combustion - it excludes upstream lifecycle emissions from crude oil extraction, refining, and fuel distribution, as well as the vehicle's own manufacturing emissions, both of which add meaningfully to a vehicle's true total carbon footprint over its lifetime.