Flight CO₂e Calculator — Airports, Cabin Class & RF Uplift
Estimate per-passenger kgCO₂e from airport distance, cabin class, one-way/return legs, optional RF uplift (×1.9), and optional per-leg overhead.
Overview
Flight footprints are usually reported as kgCO₂e per passenger for a specific route and trip type (one-way or return). The two inputs that swing results most are distance and cabin class; the RF setting can also change the total materially.
Use this thin page for a single origin → destination check. For multi-leg itineraries or mixed transport comparisons, open Master Travel CO₂. For more climate tools and assumptions, browse Energy & Environment.
- Per-passenger vs total: “Per passenger” is the unit of comparison; total trip emissions scale with the Passengers field.
- CO₂ vs CO₂e: CO₂e is a reporting unit that can incorporate non-CO₂ warming effects depending on the RF option.
- Legs: One-way = 1 leg, round trip = 2 legs (unless you model legs separately in Master Travel CO₂).
Formula/Methodology
1️⃣ Distance baseline (great-circle)
The default distance is the great-circle (shortest spherical path) between the two airports’ coordinates. It is a standard screening method, but real flights can be longer due to routing, winds, and holding.
2️⃣ Select a per-passenger factor by route type and cabin class
A single emission factor is applied in kgCO₂e per passenger-kilometer. The factor depends on route category (e.g., domestic vs international buckets) and cabin class, because larger seating footprint means higher per-passenger allocation.
3️⃣ Apply legs, RF uplift, and optional overhead
Per-passenger (kgCO₂e) = ( Distance_km × EF_class_route ) × Legs Overhead_addition Where: Legs = 1 (one-way) or 2 (round trip) EF_class_route = kgCO₂e per passenger-km factor for the chosen class/route RF enabled: apply the page's RF uplift (shown as ×1.9) to approximate non-CO₂ effects Overhead_addition = optional per-leg value (per passenger or split per flight across passengers)
| Parameter | What it changes (math/logic) | Typical range / notes | Common mistake to avoid |
|---|---|---|---|
| Origin & Destination | Defines great-circle distance between airport coordinates. | 0–18,000+ km one-way (most routes fall well below this). | Assuming great-circle equals flown distance on the day. |
| Manual distance (km) | Overrides airport distance; used directly in Distance_km × EF. |
Use one-way km; round-trip is handled by Legs. | Entering round-trip km and also selecting “Round trip” (double counts). |
| Cabin class | Selects a different EF for seat allocation (economy < premium < business < first). | Premium cabins can be multiple times economy per passenger-km. | Comparing tickets without keeping distance and RF consistent. |
| Trip type | Sets Legs to 1 or 2. |
One-way vs return is often the largest “simple” difference. | Forgetting that returns double even if dates differ. |
| RF uplift (×1.9) | Adjusts for non-CO₂ warming effects at cruise altitude. | Useful for comparing “CO₂ only” vs “CO₂ + non-CO₂” views. | Applying RF twice (uplift inside and outside the calculator). |
| Overhead per leg | Adds a fixed kgCO₂e amount per leg (optionally split per flight across passengers). | Keep small unless you have a justified add-on model. | Entering a per-passenger overhead while also splitting it per flight. |
Math checks you can do in your head
- Linearity check: doubling distance (or legs) should roughly double the distance-based part of the result.
- Units check: emission factors are per km; if you start from miles or nautical miles, convert to km first.
- RF check: if RF is on, your result should be higher than RF-off for the same inputs.
Examples
Example 1: One-way short route with RF on
Suppose a route is 1,000 km one-way, cabin class is economy, and the selected factor is 0.10 kgCO₂e/pkm.
The distance component is 1,000 × 0.10 = 100 kgCO₂e.
- One-way: 100 kgCO₂e (before optional overhead)
- With RF uplift (×1.9):
100 × 1.9 = 190 kgCO₂e - Round trip: multiply by 2 legs →
190 × 2 = 380 kgCO₂e
Example 2: Round-trip long route + overhead split across passengers
Suppose a route is 5,500 km one-way, round trip (2 legs), and the class factor is 0.25 kgCO₂e/pkm.
Distance component per passenger is 5,500 × 0.25 × 2 = 2,750 kgCO₂e.
- RF on:
2,750 × 1.9 = 5,225 kgCO₂eper passenger - Overhead (per flight): if overhead is 200 kgCO₂e per leg per flight, 2 legs = 400 kgCO₂e per flight
- Split across 4 passengers: overhead per passenger =
400 ÷ 4 = 100 kgCO₂e - Total per passenger:
5,225 + 100 = 5,325 kgCO₂e
Tip (logic): if you are comparing two flights, keep the same RF choice and the same trip type for both, otherwise you are mixing models.
Infographic & Visual Guide
How RF sits on top of “CO₂ only”
Think of aviation climate impact as CO₂ (direct emissions) plus additional high-altitude effects that are often summarized as RF (Radiative Forcing). RF is not “extra fuel burn” — it’s a reporting shortcut that approximates extra warming pathways (especially NOₓ chemistry and contrail/cirrus effects), which can vary by weather, altitude, and route.
Quality checklist (what matters for accuracy)
- RF is method-dependent: if you show a multiplier (e.g., ~1.9), label it as an illustrative screening uplift, not a universal constant.
- Avoid false precision: this is a concept graphic to explain CO₂ vs CO₂e — it does not imply exact shares for every route or flight.
- Define terms clearly: spell out RF, CO₂, and CO₂e on the visual (or in the caption) to prevent misinterpretation.
- State variability: remind users results can change with weather, altitude, route, and reporting methodology.
Use Cases
- Compare options before booking: economy vs business, direct vs longer distance, or RF-on vs RF-off for the same trip.
- Internal reporting drafts: quick screening numbers for travel requests, then refine in Master Travel CO₂ if the trip has multiple legs.
- Education and communication: show why “per passenger” changes with class, and why RF can materially change totals.
- Trip summaries: export/share a transparent estimate and keep assumptions consistent across comparisons.
Assumptions & limits (important)
- Routing: uses great-circle distance; real flight paths vary.
- Aircraft and load: uses generalized factors, not aircraft-specific fuel burn or seat maps.
- RF: represents a simplified uplift for non-CO₂ effects; scientific estimates vary by conditions and methodology.
- Scope: this thin page models one route; use Master Travel CO₂ for layovers/multi-leg journeys.
FAQ
What does “kgCO₂e per passenger” mean here?
It is the estimated kilograms of CO₂-equivalent attributed to one traveler for the selected trip (one-way or return). If you set Passengers to N, the total scales by N.
Is this CO₂ or CO₂e, and why does that matter?
The output is CO₂e (CO₂-equivalent), which is a reporting unit that can include non-CO₂ warming effects depending on the RF setting. CO₂ alone is typically lower than CO₂e.
How is the airport-to-airport distance calculated?
Distance is computed as great-circle (shortest path on a sphere) between the two airports’ coordinates. Real flight paths can be longer due to routing, winds, and holding.
What happens if I type a manual distance (km)?
A manual km value overrides the airport distance for the calculation. Use this when you already have a known one-way distance or when airports are unknown/missing.
What is Radiative Forcing (RF) and the ×1.9 uplift?
RF is a way to approximate extra warming from high-altitude effects such as NOₓ chemistry and contrail/cirrus impacts. When RF is enabled on this page, results apply an uplift shown as ×1.9 to reflect those non-CO₂ effects.
Why do business and first class show higher emissions?
Class factors allocate more emissions to larger, lower-density seating. In simple terms, fewer passengers share the same aircraft fuel burn, so the per-passenger estimate rises.
Do round-trip results simply double the one-way estimate?
Yes. This calculator assumes a symmetric return leg, so a round trip is modeled as two identical legs unless you override distance or model legs separately in the Master tool.
How does the “Passengers” field affect totals?
Most results are per passenger and then multiplied by the passenger count to give a trip total. If you enable a per-flight overhead split, that overhead is divided across passengers before adding to each traveler’s result.
What is “airport overhead per leg” used for?
It is an optional add-on in kgCO₂e to represent fixed per-leg items you want to include outside the distance factor. If treated as per-flight, it is split across passengers; otherwise it is added per passenger per leg.
What are the most common math mistakes with flight emissions?
The big ones are mixing miles and kilometers, forgetting that a return trip has two legs, and double-counting RF (applying an uplift twice). Another frequent error is entering an overhead per passenger while also splitting it per flight.
Why might my result differ from another flight CO₂ calculator?
Different tools may use different factor years, route categories, load assumptions, aircraft mixes, and RF treatments. Using great-circle distance also differs from actual routing, which varies by day and airline.
Does this include layovers or multi-leg itineraries?
No. This is a fast single-route estimate. For layovers and multi-leg trips, use the Master Travel CO₂ tool where legs can be modeled separately.
Disclaimer:
This calculator provides an estimate for educational and planning purposes. Results depend on generalized factors, route categorization, and simplified assumptions (including RF uplift). It is not a certified inventory method and does not guarantee any real-world outcome.
Last review: December 2025