A flight carbon footprint calculator built on official factors
This flight carbon footprint calculator estimates the greenhouse gas emissions of a flight in kilograms of CO₂ equivalent (CO₂e) per passenger and for your whole party. Type two airport codes or city names, pick the cabin class and the number of travellers, and it measures the great-circle distance between the airports and multiplies it by the 2026 UK government conversion factors for business air travel — the same factors many companies use for their carbon reports.
A switch adds the non-CO₂ effects of flying at altitude (radiative forcing), and both figures are always shown so you can see the difference. Nothing you type leaves your browser.
How to use the Flight Carbon Footprint Calculator
- Enter the departure and arrival airports as IATA codes (DEL, LHR, JFK) or city names; the line under each box shows which airport was found. Or switch to Distance and type the one-way flight distance.
- Choose one way or return, the cabin class and the number of passengers.
- Leave the factor set on Automatic, or pick one yourself (for example short-haul for a 1,100 km flight that does not touch the UK).
- Tick Include non-CO₂ effects if you want the headline to include radiative forcing.
- Under the comparison, type the road or rail distance if you know it and how many people would share a car, then copy the summary or download the CSV with every cabin class.
Flight Carbon Footprint Calculator features
2026 government factors
kg CO₂e per passenger-km from the UK Department for Energy Security and Net Zero, published June 2026, with and without radiative forcing, for UK domestic, short-haul, long-haul and international flights.
Cabin class matters
Economy, premium economy, business and first use different factors because premium seats take more floor space; the table shows every class on your route side by side.
1,800+ airports built in
Great-circle distance between airport reference points, the method the factors are designed for, so you do not need to look distances up.
Flight vs train, coach and car
Bars compare the trip with UK national rail, international rail, coach and an average petrol, diesel or electric car shared by the people you set.
How the calculation works
Emissions = great-circle distance × factor × number of legs × passengers. The distance comes from the haversine formula on a 6,371 km sphere. The government factors already include an 8% uplift for indirect routes, holding and delays, which is why they are applied to the plain great-circle distance; adding your own detour factor would count it twice.
The factor depends on the type of flight. Flights within the UK are domestic. Flights between the UK and Europe (including Turkey) or North Africa are short-haul; other flights to and from the UK are long-haul. Flights that do not touch the UK use the international, non-UK factors, derived from global data for the same aircraft types. Short-haul has no premium economy or first factor, so those fall back to economy and business, and domestic has only an average-passenger factor.
| Factor set (DESNZ 2026) | Economy | Business | Average passenger |
|---|---|---|---|
| Domestic, to/from UK | — | — | 135.5 g (229.3 g with RF) |
| Short-haul, to/from UK | 74.4 g (125.8 g) | 111.5 g (188.6 g) | 75.6 g (127.9 g) |
| Long-haul, to/from UK | 69.3 g (117.0 g) | 200.8 g (339.4 g) | 90.4 g (152.8 g) |
| International, to/from non-UK | 64.5 g (109.2 g) | 187.0 g (316.6 g) | 84.2 g (142.5 g) |
Radiative forcing: why there are two numbers
Burning jet fuel at cruising altitude does more than release CO₂: nitrogen oxides, water vapour and contrails also warm the climate, though how much is uncertain. The UK methodology recommends a multiplier of 1.7 on the CO₂ part of the emissions as a central estimate of these effects (based on Lee et al., 2021) and publishes separate “with RF” factors. Company reports often show both.
Worked example and limits
New Delhi (DEL) to London Heathrow (LHR) is 6,731 km on the great circle. One economy passenger, return: 6,731 × 0.06926 × 2 = 932 kg CO₂e, or 1,576 kg with radiative forcing. The same seat in business class is 2,704 kg (4,569 kg with RF), almost three times as much. A domestic hop such as Mumbai to Delhi (1,137 km) in economy is about 73 kg each way.
These are averages: a full, new, non-stop aircraft emits less per passenger than an old half-empty one, and the factors cover direct emissions from the flight only — not making the fuel (well-to-tank), airport energy or the aircraft. For a journey that has a rail option, the Distance Calculator and the Great Circle Route Map help you check distances.
Flight Carbon Footprint Calculator FAQ
How is the carbon footprint of a flight per passenger calculated?
The great-circle distance between the two airports is multiplied by an emission factor in kg CO₂e per passenger-km for the type of flight and cabin class, then by the number of legs. This calculator uses the 2026 UK government factors, which already allow for the extra distance flown compared with the straight great-circle line.
Is flying worse than taking the train?
Usually by a wide margin. With the 2026 factors, UK national rail is about 31 g CO₂e per passenger-km and international rail about 11 g, against 64–135 g for an economy or average flight seat. The bars under the result show the comparison for your own route and distance.
Is a flight worse than driving?
It depends on how many people share the car. An average UK petrol or diesel car emits about 166 g CO₂e per vehicle-km, so one person driving alone is comparable with an economy flight, while four people sharing one car emit far less each. Set the number of people per car to see your case.
Should I include radiative forcing?
If you want the fuller climate impact of flying, yes. The UK methodology suggests multiplying the CO₂ part by 1.7 to reflect non-CO₂ effects at altitude, but the true value is uncertain. This calculator shows both so you can choose and say which one you used.
Why does business class have a bigger footprint?
A business seat takes up more cabin space, so fewer passengers share the fuel burned. The government factors divide emissions by the floor area each class uses, which makes business about three times and first about four times an economy seat on long flights.
Can I use these numbers for company reporting?
They are the published UK factors for business travel, applied with the method they recommend, so they suit a Scope 3 business-travel estimate. Check whether your framework also wants well-to-tank emissions or a specific RF choice.