Flight Carbon Footprint Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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A flight’s climate footprint is not captured by distance alone. This calculator uses flight time, one-way versus return travel, seat occupancy, and a built-in non-CO₂ multiplier to create a simple passenger-level estimate. That makes the assumptions visible instead of hiding them behind a single generic emissions number.

What this calculator does

The Flight Carbon Footprint Calculator estimates kg CO₂e per passenger. It uses a base rate of 90 kg CO₂ per passenger-hour, doubles the effect with a radiative-forcing factor of 2, adjusts for one-way or return travel, and divides by the entered seat-occupancy fraction. It also shows the base CO₂ value before the radiative-forcing multiplier.

How to use it

Enter the duration of one flight leg, choose one-way or return, and enter seat occupancy as a percentage. Duration should represent airborne or trip time in the calculator’s chosen unit. If you are comparing two trips, keep the same methodology and occupancy assumptions so the difference reflects route duration rather than a change in the model itself.

How the calculation works

The current model is CO₂e per passenger = flight hours × number of legs × 90 kg CO₂/hour × 2 ÷ seat occupancy fraction. A return trip uses two legs. The without-RF metric removes the ×2 radiative-forcing multiplier but still applies the seat-occupancy adjustment.

Example

For a 3-hour flight, return travel, and 80% seat occupancy, the calculator evaluates 3 × 2 × 90 × 2 ÷ 0.80 = 1,350 kg CO₂e per passenger. Before the radiative-forcing multiplier, the same model gives 675 kg CO₂ after the occupancy adjustment.

How to interpret the result

Longer flight time, a return journey, or lower seat occupancy pushes the estimate upward. Use the result to compare scenarios generated by this specific model, especially when asking how much a second leg or a different load factor changes the total. It is not a ticket-specific emissions statement from an airline or aircraft operator.

Limitations and notes

Actual aviation emissions depend on aircraft type, route, altitude, cabin class, fuel burn, cargo allocation, load factor, and the treatment of contrails and other non-CO₂ effects. The 90 kg/hour and 2× factors are fixed assumptions in this calculator. Different accepted aviation accounting methods can therefore produce materially different answers.