Co2 Emissions Per Km
Calculator

It estimates the mass of CO2 emitted per kilometer driven, based on fuel consumption and the CO2 emission factor of the fuel type. For gasoline, this is roughly 2.31 kg of CO2 per liter burned; for diesel, roughly 2.68 kg per liter — the calculation multiplies fuel used per 100km by this factor and adjusts units.

Diesel fuel is denser and contains more carbon per liter than gasoline, so burning one liter of diesel releases more CO2 than burning one liter of gasoline. However, diesel engines are typically more fuel-efficient (fewer liters per 100km), which can partly or fully offset the higher per-liter emission factor depending on the specific vehicles compared.

People sometimes think CO2 emissions and fuel consumption are independent figures to compare separately, but CO2 output is directly and almost entirely determined by fuel burned — there's very little a vehicle can do to reduce CO2 per liter of fuel combusted, since it's a near-fixed chemistry of combustion, not an efficiency variable.

For a pure EV, there's no direct tailpipe CO2, but a full comparison requires accounting for the emissions from generating the electricity used to charge it, which varies enormously by region and grid mix — from near-zero with hydroelectric or nuclear-heavy grids to fairly high with coal-heavy grids. This calculator typically applies only to internal combustion vehicles unless it explicitly includes a grid emission factor option.

Official ratings come from standardized lab test cycles that don't fully capture real-world factors like aggressive driving, cold starts, air conditioning use, cargo load, and traffic conditions, all of which can increase actual fuel consumption and therefore actual CO2 output above the certified figure.