Flight Carbon Footprint Calculator

Estimate the CO₂ emissions of a flight.

Flight distance

Passengers(optional)

Default 1

Trips (1 or 2)(optional)

2 for round trip

Emission factor(optional)

kg/km

Default 0.15 kg CO₂e/km

Results update as you type.

CO₂ emissions

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CO₂ emissions—

How it works

Air travel is a significant source of carbon emissions, and this calculator estimates the CO₂ footprint of a flight from its distance. You enter the flight distance, the number of passengers, whether it is one-way or round trip, and optionally an emission factor, and it returns the estimated emissions in both kilograms and tonnes of CO₂-equivalent. The estimate multiplies distance by an emission factor expressed per passenger-kilometer, a widely used way to attribute a share of the aircraft's total emissions to each traveler. The default factor of about 0.15 kilograms of CO₂-equivalent per passenger-kilometer reflects a rough average for economy class; premium and business seats occupy more space and carry a larger share, while very full flights are more efficient per person. Real emissions vary with aircraft type, load factor, and flight length, since take-off and climb burn disproportionately more fuel, making short hops less efficient per kilometer. Many methodologies also apply a radiative-forcing multiplier to account for the extra warming effect of emissions at altitude, which this simple estimate omits. Use it to understand the climate impact of your travel, compare trips, and decide how much carbon to offset. Enter your flight distance and passengers to estimate the carbon footprint.

Formula

CO₂ = distance × emission factor × passengers × trips

The calculator multiplies the flight distance by an emission factor in kilograms of CO₂-equivalent per passenger-kilometer, then by the number of passengers and the number of trips. The default factor of 0.15 approximates an average economy seat. Longer flights per kilometer tend to be slightly more efficient than short hops, so this is an approximation.

Source:Aviation emissions estimation

We review all our tools from time to time to ensure accuracy.

Worked example

Flight distance:1000Passengers:1Trips (1 or 2):1Emission factor:0.15

1,000 km × 0.15 kg/km = 150 kg CO₂e, or 0.15 tonnes.

How to use this calculator

1
Enter your values
Enter flight distance.
2
Adjust the options
Adjust passengers, trips (1 or 2) and emission factor if they apply — sensible defaults are already set.
3
Read your result
CO₂ emissions updates instantly as you type — no button to press.

Frequently asked questions

How is a flight's carbon footprint calculated?

Multiply the flight distance by an emission factor in kilograms of CO₂ per passenger-kilometer, then by the number of passengers and trips. This attributes a share of the aircraft's emissions to each traveler. The calculator uses a default factor around 0.15 for economy class, which you can adjust for cabin class or a specific methodology.

What emission factor should I use?

A common average for economy class is about 0.15 kilograms of CO₂-equivalent per passenger-kilometer. Business and first class use two to four times more because seats occupy more space. Short flights are less efficient per kilometer due to fuel-heavy take-offs. Adjust the factor to match your cabin class and the methodology you prefer.

Why are short flights less efficient?

Take-off and climb consume disproportionately more fuel than cruising, so on a short flight this fuel-intensive phase makes up a larger share of the trip. As a result, emissions per kilometer are higher for short hops than for long-haul flights. This is one reason methodologies sometimes use different factors for short and long distances.

What is radiative forcing and why does it matter?

Aircraft emissions at high altitude, including contrails and nitrogen oxides, cause additional warming beyond the CO₂ alone. Many methodologies apply a radiative-forcing multiplier, often around 1.9, to reflect this. This simple calculator estimates CO₂ only, so the true climate impact of a flight may be roughly double the figure shown here.

How can I offset my flight emissions?

Once you know your flight's estimated CO₂, you can purchase carbon offsets from reputable providers that fund verified projects like reforestation or renewable energy. Offsets are priced per tonne of CO₂, so the tonnes figure here helps you buy the right amount. Reducing flights and choosing economy and direct routes cuts emissions in the first place.