Calculating your co₂ per km is straightforward once you know the CO2 Per km formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the CO2 Per km Calculator.
What is CO2 Per km?
The CO2 Per km calculation tells you your co₂ per km from a few simple inputs. The figure you are solving for here is the co₂ per km.
The CO2 Per km formula
The core formula is:
CO₂ per km = CO₂ per litre of fuel ÷ Fuel efficiency × 1000Here is what each input means:
- Fuel efficiency — a value measured in km/l. Example: 15 km/l.
- CO₂ per litre of fuel — a value measured in kg/l. Example: 2.31 kg/l.
How to calculate it step by step
- Write down the fuel efficiency (for example, 15 km/l).
- Write down the co₂ per litre of fuel (for example, 2.31 kg/l).
- Apply the formula above to get your co₂ per km.
- Double-check the result with the CO2 Per km Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Fuel efficiency | 15 km/l |
| CO₂ per litre of fuel | 2.31 kg/l |
| CO₂ per km | 154.0 |
| In kg per km | 0.1540 |
With fuel efficiency of 15 km/l and co₂ per litre of fuel of 2.31 kg/l, the co₂ per km works out to 154.0.
Example 2
With fuel efficiency of 30 km/l and co₂ per litre of fuel of 2.31 kg/l, the co₂ per km works out to 77.0.
| Result | Value |
|---|---|
| CO₂ per km | 77.0 |
| In kg per km | 0.0770 |
Example 3
With fuel efficiency of 7.5 km/l and co₂ per litre of fuel of 2.31 kg/l, the co₂ per km works out to 308.0.
| Result | Value |
|---|---|
| CO₂ per km | 308.0 |
| In kg per km | 0.3080 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the CO2 Per km Calculator does it instantly, for free, with the formula and a worked example built in.
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