Calculating your annual co₂ emissions is straightforward once you know the Car Carbon Footprint 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 Car Carbon Footprint Calculator.
What is Car Carbon Footprint?
The Car Carbon Footprint calculation tells you your annual co₂ emissions from a few simple inputs. The figure you are solving for here is the annual co₂ emissions.
The Car Carbon Footprint formula
The core formula is:
Annual CO₂ emissions = Annual distance ÷ Fuel efficiency × CO₂ per litreHere is what each input means:
- Annual distance — a value measured in km. Example: 15,000 km.
- Fuel efficiency — a value measured in km/l. Example: 15 km/l.
- CO₂ per litre — a value measured in kg/l. Example: 2.31 kg/l.
How to calculate it step by step
- Write down the annual distance (for example, 15,000 km).
- Write down the fuel efficiency (for example, 15 km/l).
- Write down the co₂ per litre (for example, 2.31 kg/l).
- Apply the formula above to get your annual co₂ emissions.
- Double-check the result with the Car Carbon Footprint Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Annual distance | 15,000 km |
| Fuel efficiency | 15 km/l |
| CO₂ per litre | 2.31 kg/l |
| Annual CO₂ emissions | 2,310 |
| Trees to offset (per year) | 110 |
With annual distance of 15,000 km, fuel efficiency of 15 km/l and co₂ per litre of 2.31 kg/l, the annual co₂ emissions works out to 2,310.
Example 2
With annual distance of 30,000 km, fuel efficiency of 15 km/l and co₂ per litre of 2.31 kg/l, the annual co₂ emissions works out to 4,620.
| Result | Value |
|---|---|
| Annual CO₂ emissions | 4,620 |
| Trees to offset (per year) | 220 |
Example 3
With annual distance of 7,500 km, fuel efficiency of 15 km/l and co₂ per litre of 2.31 kg/l, the annual co₂ emissions works out to 1,155.
| Result | Value |
|---|---|
| Annual CO₂ emissions | 1,155 |
| Trees to offset (per year) | 55 |
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 Car Carbon Footprint Calculator does it instantly, for free, with the formula and a worked example built in.
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