Estimating emissions from a car trip manually
You can make a simple estimate of a car trip’s CO2 emissions using the trip distance and the vehicle’s average fuel consumption. While online calculators provide more precision, a manual approach gives a quick sense of impact.
Steps to estimate:
- Determine trip distance in kilometres or miles.
- Know the vehicle’s average fuel consumption (e.g., litres per 100 km or miles per gallon).
- Convert fuel used into CO2: multiply fuel quantity by a standard emission factor.
Quick method example:
- If your car uses 8 litres per 100 km and your trip is 150 km, fuel used = 8 * 1.5 = 12 litres.
- Typical emission factors: petrol ~2.31 kg CO2 per litre, diesel ~2.68 kg CO2 per litre (approximate values vary by country).
- Multiply litres by the factor: 12 L * 2.31 = ~27.7 kg CO2 for the trip.
Tips to refine the estimate:
- Use the vehicle’s real-world consumption rather than manufacturer ratings if possible.
- Adjust for more efficient driving, full vs partial loads, and highway vs city driving as needed.
This manual approach provides a reasonable ballpark figure and can be used to compare different travel choices (car vs train) or to see the effect of changing driving habits. For fleet or business use, more detailed tracking is recommended.