Emissions
How much carbon each trip puts in the air
Driving and flying the same trip, measured the same way: fuel burned per seat on the plane, against electricity used by the car and how clean the grid is where you charge.
- Driving, two people
- 68 kg
- Flying, same pair
- 376 kg
- Kept out of the air
- 308 kg
- Trees for a year
- 15
Driving, two people
Flying, same pair
Kept out of the air
Trees for a year
Driving
68 kg
Flying
376 kg
The 805 km (500 mi) trip for two, charging on the world average grid.
The same trip, both ways
Two travelers, four trip lengths, charging on the world average grid (460 g of CO₂e per kWh). The car is one vehicle however far it goes. The plane is two seats burning fuel, and the gap widens with distance.
322 km (200 mi)
6.3× cleaner to drive
805 km (500 mi)
5.5× cleaner to drive
1,287 km (800 mi)
4.0× cleaner to drive
2,253 km (1,400 mi)
3.9× cleaner to drive
What the difference is worth
Take the 805 km (500 mi) trip above. Flying two people costs 376 kg of CO₂e; driving the same pair costs 68 kg. Choosing the car keeps 308 kg out of the air — once, on one weekend, for one household.
15
trees, for a year
A grown tree absorbs about 21 kg of CO₂ a year. That is how much forest it takes to undo this one flight.
13%
of a year's fair share
Holding warming near 1.5 °C means roughly 2.3 tonnes per person per year. One flight of this length eats a visible slice of it.
149
kWh to drive it
The drive pulls about 149 kWh from the grid, charging losses included. On clean electricity that is nearly carbon-free; on coal it is not.
One way. Double everything if you are coming home the same route.
Where you charge changes the answer
This is the honest reply to “your car runs on coal”. Some grids are almost carbon-free; others are among the dirtiest in the world. The same 805 km (500 mi) drive can be twenty times cleaner in one country than another — and it still beats the flight in all of them.
- Iceland28 g
- Norway30 g
- France56 g
- Brazil100 g
- New Zealand100 g
- Spain150 g
- United Kingdom210 g
- Italy310 g
- Türkiye440 g
- Japan460 g
- World average460 g
- Delaware470 g
- Australia530 g
- China580 g
- Poland660 g
- Indiana700 g
- South Africa710 g
Grams of CO₂e per kilowatt-hour of electricity delivered.
France — nuclear and hydro
45× cleaner to drive
Türkiye — close to the world average
5.8× cleaner to drive
Poland — still mostly coal
3.8× cleaner to drive
Every extra seat in the car is free
The car burns the same electricity whether one person is in it or four. Every passenger on a plane is another seat's worth of fuel. This is the single biggest lever a traveler has, and it is the part no airline can match.
1 person
2 people
3 people
4 people
How each side is counted
Flying
11 kg per passenger for taxi, takeoff and climb, then 0.2 kg per passenger-mile under 1,000 km, 0.15 kg up to 3,700 km, and 0.14 kg beyond that. Short hops are worse per kilometre because climbing is where the fuel goes.
That total is multiplied by 1.9. Contrails and high-altitude nitrogen oxides roughly double the warming effect of a flight; the accepted range is 1.7 to 2.0. Remove the multiplier entirely and flying still loses most trips, just by less.
Driving
Distance divided by 3.7 miles per kWh (about 6.0 km per kWh), times 1.1 because roughly a tenth of the energy never reaches the wheels, times the carbon intensity of the grid where the trip starts.
Grid figures are national averages for 118 regions — US states, Canadian provinces and countries across Europe, Asia, Africa, Oceania and the Americas. The world average is 460 g/kWh; the United States sits at 370 g.
Read this before you trust it
Carbon sits beside the verdict and never decides it. Sometimes this site tells you to fly even though driving is cleaner, because the trip is too long to drive. What the figure above leaves out:
Grid intensities come from Ember and the US EPA, and flight factors from the UK government's published conversion factors — each one listed, dated and linked on Sources.
- Building the car and the battery. That is a real cost, but it is paid once and spread over the whole life of the car, not this one trip.
- Building the plane, and running the airport around it.
- How full the plane is. Airlines fly close to capacity, so the per-seat figure is near reality, but a half-empty flight is much worse per passenger than this shows.
- The time of day you charge. Overnight on a windy grid is cleaner than the national average; a hot afternoon is dirtier.
- The rides to and from the airport, and the hotel night a long drive can force.
If you don't drive electric
A petrol car at 8 litres per 100 km puts out roughly 0.19 kg of CO₂e per kilometre — about 150 kg on this 805 km (500 mi) trip, close to what a single seat on that flight costs once contrails are counted. Shared between two people it is still better than flying; alone it is roughly a draw. This site models the electric case, and that is the honest comparison for everyone else.