Flight Fuel & CO2 Estimator

How this is calculated, and why it's a range

Distance starts as the great-circle line between the two airports, the same shortest-path math behind our flight time calculator. Real flights don't fly that exact line, they follow published airways and get routed around weather and traffic, so we add 6% to account for the difference before anything else gets calculated.

Fuel burn is split into two parts, because a flight doesn't burn fuel at a steady rate. Taxiing, takeoff, climb, and descent burn fuel fast and cost roughly the same amount regardless of how far you're going, so that's modeled as a fixed block per aircraft class. Cruise burns at a steadier, lower rate per hour, scaled to the flight's estimated duration. Add those two together and you get why short flights burn noticeably more fuel per mile than long ones: on a 45-minute hop, climb and descent are most of the flight, on a 10-hour crossing, they're a rounding error.

The class figures themselves are typical published averages, not a specific tail number's numbers: a widebody like an A350, 777, or 787 cruises around 5.5 to 7 tonnes of fuel an hour, a narrowbody like an A320 or 737 around 2.2 to 2.8 tonnes an hour, and a regional jet around 1.6 to 2.1 tonnes an hour. (Our post on how much fuel a plane actually uses walks through where numbers like these come from.) That range, not a single decimal, is the honest answer, actual burn depends on the specific airframe and engines, the weight on board, winds, and the altitude air traffic control actually clears the flight to.

CO2 comes straight from the fuel: burning a kilogram of jet fuel produces about 3.15 kilograms of CO2, a fixed figure from the fuel's chemistry. Per-passenger CO2 divides that total by however many people you told us are on board, or by a typical 80% full cabin at the class's typical seat count if you leave it blank, since an empty seat doesn't burn extra fuel but does change who's splitting the bill.

One more honest aside: CO2 isn't the whole climate story. Some researchers estimate a flight's total warming effect, once you count contrails and their effect on high-altitude clouds, at roughly double the CO2 figure alone. That's real ongoing science, not a settled number, so we've kept this calculator to the well-established part: the CO2 from the fuel actually burned.

Read this as a ballpark, not a boarding-pass guarantee.These numbers come from typical per-class fuel averages and a standard emissions factor, not the specific aircraft flying your route on the day. Real burn varies with the exact aircraft, how full it is, winds, altitude, and routing, sometimes substantially. Nothing here is an official figure from an airline or a carbon registry, it's a grounded estimate of scale.

If a jet ever needs to shed weight fast before landing, that fuel doesn't just get burned off, it can get dumped overboard on purpose.