To help you make more sustainable travel choices, you can find emission estimates on your flight search results and booking pages.
Find emission estimates
- Go to Google Flights.
- Search for a flight.
- On the right, click the down arrow.
- You'll find the emission estimates for each part of your trip.
Sort by emissions
- On the right, click Sort by Emissions.
- Your flight search results will be ordered from lower to higher emissions.
Filter by less emissions
- At the top, click the Emissions filter Less emissions only.
- Your flight search results will only show options with lower than typical emissions for that route.
How we calculate the tree comparison
To calculate the tree comparison, Google uses the Environmental Protection Agency (EPA) greenhouse gases equivalency calculations. The data includes how many urban tree seedlings grown for 10 years it takes to sequester the CO2e emissions. Google then takes this number to calculate an estimate for the number of trees it will take to sequester the difference in CO2e emissions (for the highlighted flight to a flight that is typical on the route) in a day.
We take the EPA calculation, convert tons to kg, and 10 years to 1 day, to get the daily estimate of CO2e sequestered per tree.
Note: Due to rounding, performing the calculations given in the equations may not return the exact results shown.
Why some flights have lower emissions
Emission estimates consider the origin, destination, aircraft type, and the number of seats in each seating class.
Factors such as fuel-efficient aircraft and shorter routes usually result in lower emissions.
The emission estimates are higher for premium economy, business, and first seating classes because the seats in these sections take up more space. They'll account for a larger share of the flight's total emissions.
Traveling by train
When a train is available on your route, you'll find it listed on your Google Flights search results.
Traveling by train may result in significantly lower emissions compared to flying. As such, train options are marked with a badge indicating lower emissions.