| # | From | To | Distance (km) | CO2/pax (kg) | CO2e/pax (kg) | Total CO2e (kg) | Copy |
|---|---|---|---|---|---|---|---|
| {{ leg.idx }} | {{ leg.fromLabel }} | {{ leg.toLabel }} | {{ leg.distanceLabel }} | {{ leg.co2Label }} | {{ leg.co2eLabel }} | {{ leg.totalCo2eLabel }} |
| Metric | Value | Copy |
|---|---|---|
| {{ row.label }} | {{ row.value }} |
Flight emissions are the greenhouse gases released as an aircraft burns fuel to move passengers from one airport to another. The number matters because it changes with route length, cabin layout, and how broadly you count climate effects, so a useful estimate is usually one that helps you compare choices rather than one that pretends to be exact.
This calculator estimates an itinerary from airport pairs or manual leg distances and returns both carbon dioxide and carbon dioxide equivalent totals. It is a practical fit for trip planning, policy discussions, or simple route comparisons where you want to see how a one-way journey differs from a return trip, or how economy differs from a higher cabin class.
The package keeps the itinerary leg by leg instead of flattening the whole trip into one opaque number. You get a route breakdown, a totals summary, a chart of leg emissions, and a JSON record, which makes it easier to see whether the biggest change came from distance, cabin selection, passenger count, or the optional climate assumptions in the advanced panel.
Airport lookup is flexible. You can type one leg per line with three-letter IATA airport codes, let the page resolve distance from a public airport registry, or append your own distance in kilometers or miles when you already know the route length or want to bypass the lookup.
The result is still a planning estimate. Real-world emissions depend on aircraft type, seating density, load factor, cargo share, routing deviations, and the accounting standard behind the number, so the safest way to use the output is to compare scenarios while holding your assumptions steady.
Start with the route itself. Each line needs two airport codes such as JFK-LHR, and the parser can also read a trailing distance like LHR-SIN 10800 or a miles value such as SFO-HND 5124 mi. That format is useful for direct flights, multi-city trips, open-jaw travel, and cases where you want to compare published route distances rather than rely on airport lookup.
Trip type and passenger count control the size of the total. A round trip doubles every resolved leg, while the traveler count multiplies the full itinerary after the per-passenger result is calculated. Cabin class changes the result too, because the tool applies a larger multiplier as seat space and assumed footprint rise from economy to premium economy, business, and first.
The advanced controls are where scenario testing becomes more interesting. Radiative forcing adds a multiplier for non-CO2 warming effects, the SAF slider applies a fixed lifecycle savings assumption to the selected fuel share, and the offset-price field turns the final total into a simple budgeting figure. None of those controls changes the underlying route, but each one changes how broadly or expensively you want to interpret the trip.
After calculation, the leg table is best for diagnosing a complicated itinerary, while the totals view is best for reporting a single answer. The chart emphasizes where the biggest contributors sit, and the JSON tab is convenient when you need a structured record. CSV, DOCX, and chart downloads make it straightforward to move the results into a travel note, report, or spreadsheet.
The tool reads each line, extracts two IATA codes, and looks for an optional manual distance. If no distance is supplied, the page loads a public airport registry, matches the airport coordinates, and computes a great-circle distance with an Earth radius of 6371 km. If a line cannot be resolved, the calculator keeps the warning and moves on instead of failing the whole itinerary.
Once distance is known, the calculation uses one of three fixed base factors expressed in kilograms of CO2 per passenger-kilometer. The script then applies the selected cabin multiplier, reduces the base CO2 by the SAF assumption, converts that result to CO2e when radiative forcing is enabled, and finally scales the answer by passenger count and trip type.
| Setting | Rule used by the package | Value |
|---|---|---|
| Short haul base factor | Distance up to 1500 km | 0.158 kg CO2 per passenger-km |
| Medium haul base factor | Distance above 1500 km and up to 3500 km | 0.139 kg CO2 per passenger-km |
| Long haul base factor | Distance above 3500 km | 0.115 kg CO2 per passenger-km |
| Economy multiplier | Baseline cabin assumption | 1.00 |
| Premium economy multiplier | Raised cabin assumption | 1.26 |
| Business multiplier | Raised cabin assumption | 1.54 |
| First multiplier | Raised cabin assumption | 2.40 |
The formulas used by the script are simple and transparent:
Radiative forcing is clamped to a range of 1.0 to 3.0 when enabled, and the SAF share is clamped to 0 to 100 percent. The summary table reports total distance, base CO2, CO2e, per-passenger values, and the resulting offset estimate so you can see exactly which assumption moved the final number.
The most useful split in the output is base CO2 versus CO2e. Base CO2 reflects the fuel-burn portion after the cabin and SAF assumptions are applied. CO2e becomes larger only when the RF setting is on, so if two scenarios have the same route and cabin but different CO2e values, the difference came from how broadly you chose to count climate effects.
Total distance is also easy to misread. The summary includes the trip multiplier, so a single 5400 km leg entered as round trip becomes 10800 km in the final distance total. The same logic applies to total CO2 and total CO2e, which is why per-passenger values are often the cleaner way to compare two itineraries before you scale the answer up for a group.
Offset cost is only a budgeting output. The package multiplies your chosen price per tonne by the calculated CO2e total, but it does not judge project quality, permanence, verification, or whether an offset purchase is appropriate. The number is best read as a spending estimate rather than as climate mitigation proof.
Warnings matter. Ignored lines mean the parser did not see two airport codes, and resolution warnings mean the tool could not derive distance for that leg. When that happens, adding a manual distance is the cleanest fix because it removes ambiguity without changing the rest of the trip logic.
Suppose you enter a single leg as LHR-SIN 10800, set the trip to round trip, choose economy, set travelers to 2, enable radiative forcing at 1.9, apply a SAF share of 30 percent, and keep the offset price at $25 per tonne. Because 10800 km is above the long-haul threshold, the script uses the 0.115 base factor.
| Stage | Calculation | Result |
|---|---|---|
| SAF reduction | 1 − 0.7 × 0.30 | 0.79 |
| Per-passenger CO2 | 10800 × 0.115 × 1.00 × 0.79 | 981.18 kg |
| Per-passenger CO2e | 981.18 × 1.9 | 1864.24 kg |
| Total CO2e | 1864.24 × 2 passengers × 2 trips | 7456.97 kg |
| Estimated offset cost | 7.45697 t × $25 | $186.42 |
In the interface, that example produces one leg row, one totals summary, and one chart bar labeled for the route with the round-trip marker. If you switch the same itinerary to business class or turn RF off, the difference becomes immediately visible because the route itself stays unchanged.
Yes. Each line becomes one leg, so you can enter simple returns, stopovers, or longer itineraries. The package totals every resolved leg after trip type and passenger count are applied.
No. Manual distances are accepted directly, which is helpful when lookup data is unavailable or when you want to match a published route assumption exactly.
It is an optional multiplier that turns base CO2 into CO2e by approximating additional warming effects associated with aviation beyond tailpipe CO2 alone. The tool does not claim that one RF value is universal; it simply lets you test the impact of that assumption.
The script treats the chosen SAF share as having a fixed 70 percent emissions savings and reduces only that share of the base CO2. It is a scenario input, not a fuel-booking verification mechanism.
The visible tool logic downloads a public airport registry, resolves coordinates for matching IATA codes, and computes great-circle distance in the browser. If the registry cannot be loaded or a code cannot be matched, the calculator asks for a manual distance for that leg.