Free tool · Carbon footprint
Flight CO2 Calculator.
How much does your flight cost the planet — and how to offset it. DEFRA 2024 methodology with high-altitude radiative forcing. No signup.
Fill the form to see your carbon footprint.
Read your footprint
Above you see total CO2, tree and car equivalents and the offset cost — the tips show how to cut it.
Frequently asked questions
How is flight CO2 calculated?+
We use the DEFRA 2024 formula: distance × emission factor per class × radiative forcing (1.9) × passengers. Distance is great-circle (Haversine).
Why does business class pollute more?+
A business seat takes ~3x the space of economy. CO2 is split across fewer passengers, so per-person emissions nearly triple (0.115 → 0.333 kg CO2/pax-km).
What is radiative forcing (RF)?+
Planes emit at altitude, where gases (NOx, water vapor, contrails) have larger climate impact. RF multiplies pure CO2 by ~1.9 to capture true warming.
Are direct flights cleaner than connections?+
Yes, ~30% less emissions on average. Takeoffs and landings burn disproportionately more fuel than cruise.
How does carbon offsetting work?+
You fund certified projects (reforestation, clean energy, methane capture) that remove or avoid equivalent emissions. Average $15-25/tonne.
Gold Standard or Verra: which to pick?+
Gold Standard is stricter on social co-benefits. Verra (VCS) has bigger volume and variety. Both are global gold standards — pick by project, not label.
Does carbon offsetting really work?+
When certified (Gold Standard, Verra, Plan Vivo), yes — but it's the last resort. Order: reduce > avoid > offset. Critics point to phantom projects, hence certification matters.
Do trains really emit 95% less than planes?+
Yes, on short routes (under 1000 km) with decarbonized electricity. Eurostar (nuclear) and Shinkansen emit ~0.04 kg CO2/pax-km vs 0.22 for planes.
Is the bus better than a plane for short trips?+
Yes. Modern coach emits ~0.03 kg CO2/pax-km. Best option after train on routes up to 600 km.
How many trees offset a flight?+
A mature tree absorbs ~25 kg CO2/year. For 1 tonne (~ São Paulo–Buenos Aires flight), that's 40 trees for 1 year.
Does Sustainable Aviation Fuel (SAF) change the math?+
Yes — SAF can cut up to 80% of fossil CO2. But it's <0.1% of aviation fuel today. Some programs offer SAF opt-in.
Are private jets much worse?+
Yes, 5–14x more emissions per passenger than commercial economy. A 4-person private jet on a light jet emits as much as 50 economy passengers on the same route.
Related reads
Scientific sources: DEFRA 2024 Greenhouse Gas Conversion Factors, ICAO Carbon Emissions Calculator Methodology, IPCC AR6 Aviation Chapter, Atmosfair Index 2024, Gold Standard Foundation, Verra VCS Standard.