How the Carbon Footprint Calculator Works
This calculator estimates your annual carbon footprint in tonnes of CO₂ equivalent (tCO₂e) by combining emission factors across four life areas: transport, home energy, diet and lifestyle spending. Emission factors are sourced from the UK Government GHG Conversion Factors, the International Energy Agency (IEA) and peer-reviewed lifecycle studies.
Transport Emissions
Car emissions are calculated using per-kilometre emission factors: petrol (0.180 kg CO₂/km), diesel (0.168), hybrid (0.105) and electric (0.053). Flight emissions use average seat-kilometre factors: short-haul (~255 kg CO₂ per flight) and long-haul (~1,560 kg CO₂ per flight), including radiative forcing uplift. Bus and train emissions use average passenger-kilometre factors (0.089 and 0.041 kg CO₂/km respectively).
Home Energy Emissions
Electricity emissions depend on your regional grid carbon intensity (kg CO₂/kWh). Countries with high renewable or nuclear capacity have very low intensity; coal-heavy grids have high intensity. Natural gas combustion emits approximately 0.203 kg CO₂ per kWh. Home energy is divided equally among household members to reflect your personal share.
Diet Emissions
Diet has a significant impact on emissions. A meat-heavy diet generates approximately 3.3 tonnes CO₂e/year through livestock production, land use and supply chains. A vegan diet reduces this to approximately 1.5 tonnes. These figures include food production, processing and transportation but not packaging.
Lifestyle Spending
Consumer goods, services and waste contribute approximately 0.5–2.0 tonnes CO₂e/year depending on spending level. This covers manufacturing, packaging, delivery and disposal of goods you purchase.
Frequently Asked Questions
What is a carbon footprint?
A carbon footprint is the total greenhouse gas emissions caused by your activities, expressed in tonnes of CO₂. It includes direct emissions (e.g. petrol you burn) and indirect emissions (e.g. electricity generation, food production).
What is the average carbon footprint per person?
The global average is around 4.7 tonnes CO₂ per year. US residents average around 14 tonnes, UK residents around 5.5 tonnes, and Indian residents around 1.9 tonnes. Scientists suggest we need to reach approximately 2.5 tonnes per person by 2030 to limit warming to 1.5°C.
What has the biggest impact on reducing my footprint?
The highest-impact individual actions are: (1) avoiding long-haul flights, (2) switching from a petrol/diesel car to an EV or public transport, (3) switching to a heat pump or renewable energy tariff, and (4) reducing red meat and dairy consumption. Even one long-haul flight can add 1.5–3 tonnes to your annual footprint.
How is electricity carbon intensity calculated?
Carbon intensity (kg CO₂/kWh) reflects how much CO₂ is emitted to generate one unit of electricity on your national grid. France is very low (~0.052) due to nuclear power; Norway is near zero (~0.010) due to hydropower; India (~0.708) and Australia (~0.656) are higher due to coal dependence.
Does offsetting my carbon count?
Carbon offsetting can play a role in a broader strategy, but reducing emissions at source is more reliable than offsets, whose quality varies widely. Use this calculator first to identify your biggest emission sources, reduce where possible, then consider certified high-quality offsets (e.g. Gold Standard) for remaining emissions.
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