Flight Carbon Calculator
The carbon dioxide equivalent (CO2e) of a flight per passenger and in total, from the distance or the airports' coordinates, using the UK government's 2026 conversion factors by flight type and cabin class.
Result…
How it's calculated
Great-circle distance d = 2R × asin(√(sin²(Δφ/2) + cos φ₁ × cos φ₂ × sin²(Δλ/2))), R = 6371.0088 km CO2e = d (km) × factor (kg CO2e per passenger-km) × flights × passengers (the DESNZ factor already includes the 8% distance uplift; 1 mi = 1.609344 km)
Works out a flight's emissions with the UK Department for Energy Security and Net Zero's Greenhouse gas reporting conversion factors 2026 (published June 2026, flat file revised July 2026): kg CO2e per passenger-km for domestic, short-haul, long-haul and non-UK international flights, by cabin class, with and without radiative forcing. Enter the distance in kilometres or miles, or the two airports' latitude and longitude for the great-circle distance by the haversine formula. DESNZ's 8% uplift for indirect routing is already in its factors, so it is shown, never added twice. Choose one way or return and the number of passengers.
Your numbers, step by step
About the Flight Carbon calculator
This flight carbon calculator estimates the greenhouse gas emissions of a flight, in kilograms of carbon dioxide equivalent (CO2e), per passenger and for your whole party. Enter the distance in kilometres or miles, or the latitude and longitude of the two airports for the great-circle distance by the haversine formula. It then uses the UK government's Greenhouse gas reporting conversion factors 2026, published by the Department for Energy Security and Net Zero (DESNZ), for domestic, short-haul, long-haul and non-UK international flights by cabin class. You see the result with and without radiative forcing, the extra warming from contrails and other effects at altitude. DESNZ already builds an 8% uplift for indirect routes and holding into its factors, so the calculator shows it rather than adding it twice. Travellers, teams logging business trips and students comparing trips can follow every step.
How to use it
- Choose how you give the distance under “Distance from”: “Distance I enter” or “Latitude and longitude”.
- Enter the “Flight distance (one way)” in kilometres or miles, or the departure and arrival latitude and longitude in decimal degrees.
- Pick the “Flight type” and “Cabin class”; any flight that does not start or end in the UK uses the international factor.
- Choose whether to include “Radiative forcing”, then set “Trip” and “Passengers”.
- Read the total CO2e, the figure without (or with) radiative forcing and the per-passenger result.
Worked example
A return economy trip from London Heathrow (about 51.47° N, 0.4543° W) to New York JFK (about 40.6413° N, 73.7781° W). The haversine great-circle distance is 5,540.0 km, which DESNZ's factor treats as 5,983.2 km flown. On the long-haul economy factor with radiative forcing, 0.11704 kg CO2e per passenger-km, one way is 5,540.0 × 0.11704 = 648.4 kg, and the return trip is 648.4 × 2 = 1,296.8 kg CO2e (about 1.30 tonnes). Without radiative forcing it is 767.4 kg.
Updated
Questions people ask
How do I calculate the carbon footprint of a flight?
Multiply the great-circle distance in km by a per-passenger-km emission factor for the flight type and cabin, then by the number of flights and passengers. The factors here come from the UK government's conversion factors 2026.
What is radiative forcing and should I include it?
It accounts for warming from contrails, water vapour and nitrogen oxides released at altitude, on top of the CO2. DESNZ recommends a multiplier of 1.7 on the CO2 part as a central estimate but calls it uncertain, so the calculator shows both figures.
Should I add extra distance for the route the plane actually flies?
No. DESNZ's factors already include an 8% uplift on the great-circle distance for indirect routes, holding and delays, so enter the straight great-circle distance between the airports.
Why does business class have a higher footprint than economy?
DESNZ shares a plane's emissions out by the floor space each seat takes. A business or first class seat takes more room, so it carries a larger share of the same flight's emissions.
Which flight type do I choose if I am not flying to or from the UK?
Choose “International, between non-UK airports”. DESNZ describes that factor as an average of its short-haul and long-haul factors for flights to and from the UK.
How accurate is a flight carbon estimate?
It is an average for the flight type and cabin, built from UK airline data. A real flight's aircraft, seating layout and how full it is can change the answer a lot. For the emissions of your home energy, use the carbon footprint calculator.