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How to use the Flight Carbon Calculator
- 1Choose your departure and destination cities.
- 2Pick one-way or return, cabin class and number of passengers.
- 3Optionally choose the aircraft type to see how much difference it makes.
Why cabin class matters
Business and first-class seats take up much more space than economy, so each passenger is responsible for a bigger share of the plane's fuel. On long-haul flights, business class has about 2.9× and first class about 4× the footprint of economy.
Non-CO₂ warming (radiative forcing)
At cruising altitude, aircraft also cause warming through contrails and nitrogen oxides. The UK government recommends including this effect, which roughly doubles the CO₂-only figure. You can switch it off to see CO₂ alone.
Does the aircraft type matter?
Yes. New-generation aircraft like the A320neo, 737 MAX, 787 and A350 burn roughly 15–25% less fuel per passenger than the older models they replace, while the giant A380 is surprisingly inefficient per passenger. Private jets emit around 10 times more per passenger than airliners.
Choosing carbon offsets
If you offset a flight, choose projects certified by a recognised standard such as Gold Standard or Verra, prefer permanent carbon removal over avoided-emission credits, and remember that flying less, flying economy and choosing direct flights cut emissions more reliably than offsetting.
Frequently asked questions
How much CO2 is a flight from London to New York?
A return economy trip is about 12,000 km and emits roughly 1.4 tonnes of CO₂e per passenger including non-CO₂ effects, about 70% of a sustainable yearly carbon budget.
Are short flights worse?
Per kilometre, yes: take-off and climb use a lot of fuel, so short flights have the highest emissions per km. Trains are usually a far lower-carbon alternative for trips under about 700 km.