Transport
Home Energy
Diet & Lifestyle
Petrol per km
CO₂ emission factor for an average petrol/gasoline car
One long flight
Estimated CO₂e for a single long-haul return flight (>3h)
Heavy meat diet
Annual dietary footprint for a heavy meat eater
Vegan diet
Annual dietary footprint for a plant-based diet
80% of Your Footprint Hides in Three Places
Flight emissions, red meat consumption, and home heating account for the lion's share of most personal carbon footprints. Small changes in those three areas outperform dozens of smaller optimisations combined.
What Your Carbon Footprint Actually Means
The average global per-capita footprint is approximately 4.7 tonnes CO₂e per year. For the 1.5°C Paris target to be met, this needs to fall to roughly 2 tonnes per person by 2030. The average American emits ~14–16t; the average European 7–9t.
The calculator uses established emission factors from IPCC and governmental sources. Treat the result as a directional guide, not a precise measurement — but the relative size of each category is reliable and actionable.
Scope 3 emissions (embedded in goods and services you consume) are not captured here — they typically add another 30–50% to your total. Reducing them requires behaviour change beyond what this calculator tracks.
The Moves That Actually Matter
Go plant-rich (saves 0.5–2.5t/yr)
Moving from heavy meat to vegetarian saves ~1.5t CO₂ per year. Going vegan saves ~2.5t. Even reducing beef and lamb to once a week makes a measurable difference.
Fly less (saves 0.5–3t per flight)
One transatlantic return flight emits ~1.5–3t CO₂e. Skipping one long-haul flight per year is equivalent to switching to an electric car for most people.
Switch to EV & heat pump (saves 1–3t/yr)
Replacing a petrol car with an EV on the average grid saves ~1–2t per year. A heat pump replacing a gas boiler saves a similar amount for a typical home.
Frequently Asked Questions
Formula & Calculation Method
Annual Carbon Footprint
CO₂e = Σ (Activity_i × EmissionFactor_i)CO₂e— Carbon dioxide equivalent in kg or tonnes per yearActivity_i— Quantity of each activity (e.g., km driven, kWh consumed)EmissionFactor_i— Emissions per unit (e.g., 0.18 kg CO₂/km for petrol car)
Source: GHG Protocol Corporate Standard / IPCC AR6
Diet Emissions (per person/year)
Diet_CO₂ ≈ {heavy-meat: 3.3t, meat: 2.5t, flexitarian: 1.9t, vegetarian: 1.7t, vegan: 1.5t}Source: Scarborough et al., Climatic Change (2014); Poore & Nemecek, Science (2018)
Authoritative Sources & Standards
- EPA: US EPA passenger vehicle average: 4.6 metric tons CO₂/year (2024). Electric grid emissions: 0.4 kg CO₂/kWh (US average, declining ~3%/year). → EPA
- IPCC: IPCC AR6 (2021): Global warming budget remaining for 1.5°C target = ~400 GtCO₂ from 2020. Annual per-capita budget for 1.5°C: ~2.3t CO₂ by 2030. → IPCC
Expert Insights & Research
Top 4 personal interventions ranked by CO₂ reduction (Wynes & Nicholas, 2017): 1. Have one fewer child (58.6 tCO₂/year saved), 2. Live car-free (2.4t), 3. Avoid one transatlantic flight (1.6t), 4. Plant-based diet (0.8t).
Animal agriculture produces 14.5% of global GHG emissions — more than all transport combined (10–14%). Beef has 60× the CO₂ footprint of legumes per gram protein.
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For informational purposes only — not financial, medical, or legal advice. Results are estimates; use at your own risk. Full terms