Carbon Market Network
Flight Emissions Tool
Know the true carbon cost of any flight
Estimate the CO₂ and CO₂e footprint of a flight using great-circle distance, cabin class, and internationally recognized emission factors. Enter two airports to get an instant, methodology-backed estimate.
ICAO-aligned distance model
DEFRA-style cabin weighting
IPCC-informed CO₂e
90+
Airports covered
4
Cabin classes modeled
<1s
Calculation time
Route & passenger details
CO₂e est.
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0kg CO₂
Estimated CO₂ emissions
0kg CO₂e
Total climate impact (CO₂ only)
Estimated carbon credits to offset: 0 (1 credit = 1 tonne CO₂e, rounded up)
Based on great-circle distance with a route-inefficiency adjustment, fleet-average fuel burn for this distance band, an 80% load factor, and DEFRA-style cabin class weighting.
How We Calculate Flight Emissions
This calculator follows the same general approach used by major aviation emissions tools, built from publicly documented methods rather than airline-specific or proprietary data.
Distance
Haversine great-circle distance
We calculate the shortest path between two airports over the Earth’s curved surface using the Haversine formula, then add a fixed adjustment for the extra distance flown due to routing, holding patterns, and departure/arrival vectoring rather than a straight line.
ICAO-aligned
ICAO-style fuel burn bands
Fuel burn per seat is estimated from fleet-average rates across three distance bands (short, medium, and long haul), reflecting the same distance-based logic used in the ICAO Carbon Emissions Calculator, since aircraft burn proportionally less fuel per kilometre on longer sectors.
DEFRA-style
Cabin class allocation
A business or first-class seat occupies more of the aircraft’s total space and weight budget than an economy seat. We apply DEFRA-style class weighting factors (economy 1.0× up to first class 4.0×) to allocate a fair share of total aircraft emissions to each passenger.
IPCC-informed
Radiative forcing (optional)
Aviation warms the climate through more than CO₂ alone, including contrails and NOx effects at altitude. When enabled, we apply an IPCC-informed radiative forcing multiplier of roughly 1.9× to CO₂ to approximate total climate impact, shown separately as CO₂e since the underlying science carries wider uncertainty than the CO₂ figure itself.
Stated assumptions. Exact aircraft type, engine variant, winds, and load factor are not knowable for a general-purpose calculator, so we use documented industry averages instead of guessing at precision we don’t have:
- Route-inefficiency adjustment of approximately 95 km added to great-circle distance
- Fleet-average fuel burn per seat by distance band, not a specific aircraft or engine type
- Default load factor of 80% (adjustable), consistent with published industry averages
- CO₂ emitted per kilogram of jet fuel burned: 3.16 kg, a standard factor used across ICAO and DEFRA methodologies
- Radiative forcing multiplier of ~1.9× when non-CO₂ effects are enabled, an area of ongoing scientific refinement
Because of these averages, results are designed to sit close to figures from the ICAO Carbon Emissions Calculator, DEFRA’s methodology, Google Flights’ emissions estimates, and major airline sustainability calculators, but will not match any single one exactly. Airline-published figures use their own live fleet and load data, which we do not have access to.
Frequently Asked Questions
Common questions about flight emissions, offsetting, and how this calculator works.
How accurate is this calculator?+
It is designed for close alignment with recognized methodologies, not laboratory precision. Because actual emissions depend on aircraft type, winds, air traffic routing, and how full the flight is, any calculator, including airline-published tools, produces an estimate. This tool aims to sit within a reasonable range of the ICAO calculator, DEFRA’s published factors, and typical airline sustainability tools for the same route and cabin class.
What is radiative forcing?+
Radiative forcing describes the additional warming effect of aviation beyond its CO₂ emissions alone, including contrails, cirrus cloud formation, and nitrogen oxide emissions released at cruising altitude. Because these effects are still being refined scientifically, they are shown as an optional multiplier rather than folded silently into the headline CO₂ figure.
Should I offset my flight?+
Offsetting does not eliminate a flight’s emissions, but it can fund emission-reduction or removal projects elsewhere, such as renewable energy, methane capture, or reforestation, that would not otherwise happen. Many organizations treat offsetting as one part of a wider approach that starts with reducing flights where practical, choosing more efficient routings or aircraft, and offsetting what remains through verified projects.
How many carbon credits do I need?+
One carbon credit typically represents one tonne of CO₂e avoided or removed. Divide your flight’s total CO₂e figure in kilograms by 1,000 and round up to get the number of credits needed to offset it fully. This calculator does that conversion automatically in the results panel above.
How much CO₂ does flying produce?+
It varies significantly by distance, aircraft, and cabin class, but as a general pattern, short domestic flights produce more CO₂ per kilometre than long-haul flights because takeoff and climb are fuel-intensive relative to cruise. Business and first-class seating also carries a higher per-passenger share of emissions than economy, since it occupies more of the aircraft’s space and weight.
What is CO₂e?+
CO₂e, or carbon dioxide equivalent, expresses the combined warming effect of multiple greenhouse gases or climate effects in terms of the amount of CO₂ that would cause the same warming. For flights, CO₂e can include aviation’s non-CO₂ effects, such as contrails, in addition to the CO₂ itself.
How do carbon offsets work?+
A carbon offset represents a verified reduction or removal of one tonne of CO₂e achieved by a project, such as a wind farm displacing fossil fuel generation or a forest conservation program preventing deforestation. Buying and retiring an offset credit is intended to compensate for emissions generated elsewhere, such as from a flight, provided the underlying project is genuinely additional and independently verified.
Are carbon credits verified?+
Credible carbon credits are independently verified against a recognized standard, such as Verra’s Verified Carbon Standard, Gold Standard, the American Carbon Registry, or the Climate Action Reserve, which each require third-party auditing, additionality testing, and a public registry entry before a credit can be issued and retired. Not all credits on the market meet the same bar, so checking the issuing standard and registry listing is a reasonable first step before purchasing.
Can businesses use this calculator?+
Yes. The methodology is suitable for estimating business travel emissions for internal reporting or Scope 3 travel categories, though organizations with formal disclosure requirements, such as CSRD or GHG Protocol reporting, should confirm whether their reporting framework requires a specific calculation tool or emission factor source before relying on any single calculator for compliance purposes.