🌍 Driving Carbon Footprint Calculator
Enter your annual miles and MPG to estimate the CO₂ your driving puts into the air each year — with an optional comparison against an electric car.
🌱 Estimate Your Driving Emissions
🌍 Annual driving emissions at 25.0 MPG
What is a Driving Carbon Footprint Calculator?
It converts your yearly driving into the carbon dioxide it releases. Because CO₂ is tied directly to the fuel burned, the maths is simple and reliable: fewer gallons means less carbon, and a higher MPG or fewer miles both move the number down.
The emission factor is kept as a documented constant — the EPA's 8.887 kg of CO₂ per gallon of gasoline — so the estimate is transparent and reproducible. Switch on the electric-car comparison to see how the same miles stack up when powered from the grid at your region's carbon intensity.
❓ Frequently Asked Questions
How is driving CO₂ calculated?
The calculator divides your annual miles by your MPG to find the gallons of gasoline burned each year, then multiplies by 8.887 kg of CO₂ per gallon — the US EPA emission factor for gasoline. The result is shown in both kilograms and metric tons per year.
Where does the 8.887 kg per gallon figure come from?
It is the US Environmental Protection Agency's tailpipe emission factor for a gallon of gasoline, from its guidance on greenhouse gases from a typical passenger vehicle. Burning one gallon releases about 8.887 kilograms of carbon dioxide.
Does this include the emissions from making the fuel?
No. This is tailpipe CO₂ only — the carbon released when the fuel is burned. Well-to-wheel accounting that adds refining and distribution raises the figure by roughly a quarter, but tailpipe emissions are the standard, comparable baseline.
How does the electric-car comparison work?
If you turn on the EV comparison, the tool multiplies your annual miles by the EV's kWh per 100 miles to get yearly energy use, then multiplies by a grid carbon intensity (defaulting to the US average of about 0.386 kg CO₂ per kWh). A cleaner local grid lowers the EV figure; a coal-heavy one raises it.