Flight Carbon Footprint Calculator
Work out the CO2e of a flight for each passenger and in total: pick two airports or type a distance, choose your cabin and trip, and see it with or without the extra warming at altitude.
Hamad International Airport · OTHH · Qatar
London Heathrow Airport · EGLL · United Kingdom
Great-circle distance, as on a ticket or flight-distance site.
Contrails and other high-altitude effects add roughly 70% more warming (radiative forcing).
For example 6 for a trip you make every two months.
Used when non-CO2 effects are included. DESNZ uses 1.7.
Auto: under 500 km domestic, up to 3,700 km short-haul, beyond that long-haul.
Turn off if your distance is the one actually flown.
Prices vary a lot by project and provider. Type the one you were quoted.
From your car’s papers or maker. Shows how far you could drive for the same CO2.
Factors used: kg CO2e per passenger-km, without non-CO2 effects (check the current figure)
UK Government (DESNZ) greenhouse gas conversion factors 2025, business travel: air. These are starting figures: check each one against the current spreadsheet on gov.uk and type the latest value. DESNZ gives one average figure for domestic flights and only economy and business for short-haul, so the other cabins repeat those. "International" starts at the long-haul figures.
How your flight footprint is worked out
Distance, plus 8%, times a factor per passenger-km.
- 1
Flight distance
DOH → LHR5,241 km
- 2
Add 8% for routing
5,241 km × 1.08= 5,661 km
- 3
Times the factor
× 0.0775 kg/kmeconomy, long-haul= 439 kg
- 4
Your whole trip
439 kg × 2 return= 877 kg each
Read more: the formula, a worked example, the factors and notes
The calculator takes the shortest distance between the airports (the great circle), adds 8% because real flights take a longer path, and multiplies by a factor for your distance band and cabin. That gives kg of CO2e for one passenger one way. It then doubles it for a return trip, multiplies by the trips and passengers, and adds the non-CO2 multiplier if you choose it.
The formula
distance flown = great-circle km × 1.08
CO2e per passenger, one way = distance flown × factor for the band and cabin (kg per passenger-km)
with non-CO2 effects = CO2e × 1.7
per passenger = one way × 2 for a return × trips
total = per passenger × passengers
offset cost = tonnes × your price per tonne · car distance = kg ÷ your car’s kg per km
Worked example
Doha Hamad (DOH) to London Heathrow (LHR) is 5,241.47 km on the great circle. That is over 3,700 km, so it is a long-haul flight. Adding 8%: 5,241.47 × 1.08 = 5,660.79 km. In economy the factor is 0.0775 kg CO2e per passenger-km, so one way is 5,660.79 × 0.0775 = 438.71 kg. A return trip is 438.71 × 2 = 877.42 kg, or 0.877 tonnes, per passenger. Including non-CO2 effects it is 877.42 × 1.7 = 1,491.61 kg.
In business class the long-haul factor is 0.2247, so one way is 5,660.79 × 0.2247 = 1,271.98 kg, which is 2.9 times the economy figure. If you were quoted an offset price of 15 per tonne, the economy return trip would cost 0.87742 × 15 = 13.16 in your currency.
Starting factors (kg CO2e per passenger-km, without non-CO2 effects)
| Band | Economy | Premium economy | Business | First |
|---|---|---|---|---|
| Domestic | 0.1338 | 0.1338 | 0.1338 | 0.1338 |
| Short-haul | 0.0790 | 0.0790 | 0.1185 | 0.1185 |
| Long-haul | 0.0775 | 0.1240 | 0.2247 | 0.3100 |
| International (not to or from the UK) | 0.0775 | 0.1240 | 0.2247 | 0.3100 |
Factor set: UK Government (DESNZ) greenhouse gas conversion factors 2025, business travel: air (published 10 June 2025). Checked on 17 Oct 2026 at gov.uk: Greenhouse gas reporting: conversion factors 2025. That page gives the factors only inside its Excel files (condensed set, full set and flat file), which we could not open when checking, so the figures above are starting values that have not been confirmed against the spreadsheet. Check the current figure there and type it into “Factors used” in Advanced. The same goes for the 8% routing extra, the 1.7 non-CO2 multiplier and the distance bands, which follow the DESNZ method paper published alongside.
Distance bands
- Domestic: DESNZ means flights inside the UK. Here any flight under 500 km uses it.
- Short-haul: flights to or from the UK up to about 3,700 km. Here any flight from 500 to 3,700 km.
- Long-haul: flights to or from the UK over about 3,700 km. Here anything longer.
- International: DESNZ also publishes a set for flights that neither start nor end in the UK. Pick it under Distance band and type its current figures.
Good to know
- Each leg of a trip with a stop is banded on its own, so two short flights can come out differently from one long one.
- These are averages for a typical aircraft and load. Your airline, aircraft type and how full the plane is all change the real figure.
- CO2e (carbon dioxide equivalent) includes small amounts of methane and nitrous oxide, converted to the same warming as CO2.
- Offsets differ in quality and price. The calculator only multiplies your price by the tonnes; it does not recommend any scheme.
Airport positions are from OurAirports (public domain). This is an estimate for planning and comparison, not a figure for official reporting.
Common questions
How much CO2 does a flight from Doha to London produce per passenger?
Doha (DOH) to London Heathrow (LHR) is 5,241 km along the great circle. With 8% added for routing and a long-haul economy factor of 0.0775 kg CO2e per passenger-km, one way is about 439 kg CO2e and a return trip about 877 kg. Including non-CO2 effects at altitude (× 1.7) the return trip is about 1.49 tonnes. Check the factor against the current UK Government (DESNZ) spreadsheet.
Why does business class have a bigger footprint than economy?
The plane burns the same fuel whoever sits where, so the emissions are shared out by floor space. A business seat takes up about three times the room of an economy seat, so it gets about three times the share. On a long-haul flight the starting factors here are 0.0775 kg per km for economy and 0.2247 for business.
What is radiative forcing on a flight?
Planes affect the climate in ways other than CO2: contrails, cirrus clouds and nitrogen oxides at cruise height add extra warming. The UK Government factors show this as a separate "with RF" set, roughly 1.7 times the CO2-only figure. Scientists still debate the exact size, so the calculator lets you show both and change the multiplier.
Why add 8% to the flight distance?
Real flights rarely fly the shortest great-circle path. Air-traffic routes, holding and weather detours make them a little longer. The UK Government method adds 8% to the great-circle distance to allow for this. Turn it off if the distance you type is the distance actually flown.
How much does it cost to offset a flight?
Multiply the tonnes of CO2e by the price per tonne your offset provider charges. Prices vary a lot between projects and providers, so the calculator does not assume one: type the price you were quoted. At a price of 15 per tonne, a 0.88 tonne return trip would cost about 13.16 in your currency.
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