How is a car's CO2 emission calculated?

It first finds fuel used (L) = distance (km) ÷ fuel economy (km/L), then CO2 (kg) = fuel used (L) × emission factor. The factors are about 2.32 kg-CO2/L for gasoline and 2.58 kg-CO2/L for diesel.

How is this different from the fuel-saving tool?

This tool calculates the actual fuel used, fuel cost, and CO2 for a given distance and economy. If you want the money and CO2 you would save by improving fuel economy, use the fuel-saving effect tool instead.

What is the per-kilometer CO2 figure useful for?

It shows CO2 emitted per kilometer, so you can compare the environmental impact of different cars or driving styles on the same basis. The factor is a Tank-to-Wheel combustion value and excludes production and transport, so it is an estimate.

Car Fuel & CO2 Emissions

Enter your driving distance, fuel economy, fuel type, and fuel price to instantly estimate fuel consumption (L), fuel cost, and CO2 emissions. Supports gasoline and diesel, and also shows CO2 emitted per kilometer.

Last updated: June 25, 2026

Input

Enter your driving distance, fuel economy, fuel type, and fuel price to estimate fuel consumption, fuel cost, and CO2 emissions.

Distance

Fuel economy

km/L

Fuel type

Fuel price

Result

CO2 emissions (Gasoline (regular))

15.5kg

= 15,467 g-CO2 (estimate)

Fuel used

6.67 L

Fuel cost

$1,166.67

CO2 per km

155 g/km

Calculation breakdown

Item	Value
Distance	100.0 km
Fuel economy	15.0 km/L
Fuel used (distance / economy)	6.67 L
CO2 emission factor (Gasoline (regular))	2.32 kg-CO2/L
CO2 emissions (fuel x factor)	15.5 kg

How it works

Fuel consumption is derived from distance and fuel economy, then used to estimate fuel cost and CO2 emissions. Fuel used (L) = distance (km) / fuel economy (km/L).
CO2 emissions (kg) = fuel used (L) x emission factor. Representative factors of about 2.32 kg-CO2/L for gasoline and about 2.58 kg-CO2/L for diesel are used.
Fuel cost = fuel used (L) x fuel price per liter. Fuel prices vary widely by country and over time, so enter your local price for an accurate estimate.
CO2 emitted per kilometer is also shown, making it easy to compare the environmental impact of different vehicles or driving styles.
Emission factors are representative Tank-to-Wheel values from fuel combustion and exclude production and transport. Actual emissions are an estimate that varies with driving conditions and vehicle.

Frequently asked questions

How is a car's CO2 emission calculated?: It first finds fuel used (L) = distance (km) ÷ fuel economy (km/L), then CO2 (kg) = fuel used (L) × emission factor. The factors are about 2.32 kg-CO2/L for gasoline and 2.58 kg-CO2/L for diesel.
How is this different from the fuel-saving tool?: This tool calculates the actual fuel used, fuel cost, and CO2 for a given distance and economy. If you want the money and CO2 you would save by improving fuel economy, use the fuel-saving effect tool instead.
What is the per-kilometer CO2 figure useful for?: It shows CO2 emitted per kilometer, so you can compare the environmental impact of different cars or driving styles on the same basis. The factor is a Tank-to-Wheel combustion value and excludes production and transport, so it is an estimate.

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