What is a carbon footprint and how is it measured?

A carbon footprint is the total greenhouse gas emissions caused by an individual, organization, event, or product, expressed in tonnes of CO2 equivalent (CO2e). It includes direct emissions (burning fuel) and indirect emissions (purchased electricity, supply chain). This calculator uses EPA and DEFRA emission factors to convert your activities into CO2e, following the GHG Protocol methodology.

What's the difference between Scope 1, 2, and 3 emissions?

Scope 1: Direct emissions from owned/controlled sources (company vehicles, on-site fuel combustion, refrigerant leaks). Scope 2: Indirect emissions from purchased energy (electricity, steam, heating, cooling). Scope 3: All other indirect emissions in your value chain (business travel, employee commuting, purchased goods, waste disposal). Scope 3 typically represents 70-90% of a company's total footprint.

What is the Paris Agreement 2030 target for personal carbon footprint?

The Paris Agreement aims to limit global warming to 1.5°C. To achieve this, the average global carbon footprint needs to drop to approximately 2.5 tonnes CO2e per person by 2030, down from the current global average of 4.8 tonnes and the US average of 16 tonnes. This calculator shows how your footprint compares to this target.

How does diet affect carbon footprint?

Diet is a major contributor, accounting for 10-30% of personal emissions. Heavy meat eaters emit ~3.3 tonnes CO2e/year from food alone, while vegans emit ~1.5 tonnes. Beef produces 20x more emissions than beans per gram of protein. Reducing meat consumption, choosing local/seasonal produce, and minimizing food waste are the most impactful dietary changes.

What's the carbon footprint of flying vs driving?

A round-trip transatlantic flight (economy) produces ~1.6 tonnes CO2e per passenger—equivalent to driving 6,000 miles in an average car. Business class is 3x higher due to more space per passenger. Short-haul flights are even less efficient due to takeoff/landing fuel intensity. One long-haul flight can equal 1-2 years of car commuting.

How do I calculate my electricity carbon footprint?

Multiply your annual kWh consumption by your region's grid emission factor. US average is ~0.42 kg CO2e/kWh, but varies widely: California (0.22) to Wyoming (0.84). If you use 100% renewable energy, your electricity emissions are effectively zero. This calculator adjusts for regional grid mix and renewable percentage.

What are carbon offsets and do they work?

Carbon offsets fund projects that reduce emissions elsewhere (reforestation, renewable energy, methane capture). Quality varies significantly—look for verified standards like Gold Standard or Verra VCS. Offsets should complement, not replace, direct emission reductions. Prioritize reducing your footprint first, then offset unavoidable emissions.

How many trees does it take to offset my carbon footprint?

A mature tree absorbs approximately 22 kg CO2 per year. To offset the average American's 16 tonnes annually, you'd need ~727 trees. However, trees take decades to reach full absorption capacity. This calculator shows tree equivalents to help visualize your impact, but actual offsetting requires verified programs.

Carbon Footprint Calculator

Calculate your personal or business carbon footprint in tonnes CO₂e. Compare to Paris 2030 targets, see EPA/DEFRA emission breakdowns, and get reduction tips.

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About This Calculator

This comprehensive carbon footprint calculator estimates your annual greenhouse gas emissions based on your lifestyle choices. It uses emission factors from EPA (US), UK DEFRA, and ADEME (EU) databases.