Car CO2 Emissions Calculator
Estimate your vehicle’s CO₂ output from fuel type and consumption — understand your environmental footprint.
CO₂ Emissions Calculator
Fuel type · Consumption · Carbon output
How It Works
CO₂ emissions are calculated by multiplying litres of fuel consumed by the fuel-specific emission factor. Petrol produces approximately 2.31 kg CO₂ per litre, diesel approximately 2.68 kg/L.
How to Use This Calculator
- Select your fuel type (petrol or diesel).
- Choose whether to enter litres used directly or calculate from distance and economy.
- Fill in the relevant fields.
- Click Calculate to see total CO₂ in kg.
- Compare different journeys or fuel types to find the lower-carbon option.
Worked Example
Reference Table
| Fuel Type | CO₂ kg/L | CO₂ g/km @8L/100 | Annual kg @15k km |
|---|---|---|---|
| Petrol | 2.31 | 184.8 | 3,119 |
| Diesel | 2.68 | 214.4 | 3,618 |
| E10 petrol | 2.24 | 179.2 | 3,024 |
| E85 ethanol | 1.61 | 128.8 | 2,172 |
| LPG/Autogas | 1.63 | 130.4 | 2,200 |
Frequently Asked Questions
Why do petrol and diesel have different CO2 emission factors?
Diesel has more carbon atoms per litre (higher energy density). Although diesel engines are more fuel-efficient and emit less CO₂ per km, diesel combustion also produces more particulates and NOx, which is why emission standards treat them differently.
What is the average CO2 output per km for a typical car?
The EU average for new passenger cars is around 118 g CO₂/km (2023 data). A car emitting over 200 g/km is a high emitter; below 100 g/km is efficient. Full EVs report near-zero tailpipe emissions.
Does air conditioning affect CO2 emissions?
Yes — AC can increase fuel consumption 5–25% depending on climate and load, directly increasing CO₂ emissions proportionally. At highway speeds the impact is smaller; at low city speeds it can be significant.
How do electric vehicles compare for CO2 emissions?
EVs have zero tailpipe emissions but their lifecycle CO₂ depends on the electricity grid mix. In countries with high renewable energy penetration, an EV typically emits 70–90% less CO₂ over its lifetime compared to a petrol car.
