Tool
Car Trip Emissions Estimator
Estimate CO2 for a car trip by distance, fuel type and consumption, with per-passenger figures.
Method
UK DEFRA 2024 combustion factors: petrol 2.0844 kg/L, diesel 2.5128 kg/L; electric uses the editable grid factor (UK default 0.20705 kg/kWh).
Limitations
Combustion-only for petrol/diesel; vehicle manufacture, road and well-to-tank emissions are excluded and stated in the tool.
Car trip emissions estimator
[object Object] [object Object] [object Object]
Enter a distance and a consumption figure to see the result.
Result: 0.00 kg CO2e for the trip (0.00 tonnes)
- Fuel used: 0.00 litres
- Per passenger (1 person): 0.00 kg
- Per 100 km: 0.00 kg
Combustion only (electric: grid factor shown). Excludes vehicle manufacture and well-to-tank fuel supply. Sources: DESNZ/DEFRA Conversion Factors 2024.
Frequently asked questions
What does the Car Trip Emissions Estimator calculate?
It estimates CO2 for a single car trip from distance, fuel type and consumption, showing total emissions, emissions per passenger and emissions per 100 km.
Which factors does the car trip tool use?
It uses UK DEFRA 2024 combustion factors: petrol 2.0844 kg per litre and diesel 2.5128 kg per litre. Electric cars use the editable grid factor, pre-filled with the UK 2024 figure of 0.20705 kg per kWh.
How is the per-passenger figure calculated?
The total trip emissions are divided by the number of passengers you enter. If you enter zero passengers, the tool falls back to one passenger so it never divides by zero.
What is excluded from the car trip estimate?
Vehicle manufacture, road construction and well-to-tank fuel production are excluded. The factors are combustion-only for petrol and diesel, as stated on the tool page.
Can I compare a petrol, diesel and electric trip?
Yes. Run the same distance with each fuel type and the same grid factor for the electric case, then compare the totals. Keep the grid factor consistent, or the comparison will not be like for like.