How is CO₂ emissions from a car trip calculated?

Fuel used (Distance ÷ Fuel efficiency) is multiplied by the emission factor for your fuel type. For a 100 km trip at 15 km/l on petrol, that's (100 ÷ 15) × 2.31 ≈ 15.4 kg CO₂.

Why does the emission factor differ between petrol, diesel and CNG?

Each fuel releases a different amount of CO₂ per litre or kg when burned, based on its carbon content: petrol is about 2.31 kg CO₂/L, diesel about 2.68 kg CO₂/L (denser and more carbon per litre), and CNG about 1.94 kg CO₂/kg. Selecting the correct fuel type gives a more accurate estimate.

Carbon Emissions Calculator

Estimate CO₂ emissions from a car trip based on fuel type and efficiency.

How this is calculated

Emissions = (Distance ÷ Fuel efficiency) × Emission factor

Assumptions used in this calculation

Emission factors: Petrol ≈ 2.31 kg CO₂/L, diesel ≈ 2.68 kg CO₂/L, CNG ≈ 1.94 kg CO₂/kg.

About this calculator

The carbon emissions calculator estimates the CO₂ emitted by a car trip based on distance, fuel efficiency and the fuel's emission factor.

Worked example

100 km at 15 km/l, petrol

Result: 15.4 kg CO₂

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Frequently asked questions

How is CO₂ emissions from a car trip calculated?

Why does the emission factor differ between petrol, diesel and CNG?

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