How much CO2 does your flight really produce? How to know if carbon footprint claims are accurate

Vladimir Sukhachev/Shutterstock

When two people book the same flight, they can get wildly different carbon footprints from online calculators. Many carbon calculators leave out big chunks of climate impact or rely on oversimplified assumptions.

Here’s what’s missing, why it matters and a practical checklist you can use to judge any flight estimate.