Carbon Footprint Calculator
Estimate yearly CO₂ from driving and home electricity.
Results update as you type.
How it works
A carbon footprint measures the greenhouse gases your activities release, expressed as an equivalent weight of carbon dioxide. This carbon footprint calculator focuses on two of the largest household sources — the car you drive and the electricity your home consumes — and reports your yearly emissions in metric tons of CO₂, split so you can see which source dominates. Driving emissions come from burning fuel: the fewer miles you cover and the more efficient your vehicle, the less carbon you produce. Home emissions depend on how much grid electricity you use and how clean that grid is. Because both are scaled by published emission factors, the result is a realistic estimate rather than a rough guess, giving you a baseline to act on. Knowing your footprint matters because it turns an abstract climate concern into concrete numbers you can influence. Switching to a more efficient car, driving less, improving home insulation, or moving to renewable electricity each shifts the figure measurably. Individuals tracking sustainability goals, families comparing lifestyle changes, and students learning about emissions all use a carbon footprint calculator to understand impact and target the changes that cut the most carbon for the least effort in daily life.
CO₂ = (miles ÷ mpg × 8.887) + (kWh × 12 × 0.417), in kg ÷ 1000
Each gallon of gasoline burned releases about 8.887 kilograms of carbon dioxide, so dividing your annual miles by fuel economy gives gallons, which multiplied by that factor gives driving emissions. Home electricity uses a grid factor of roughly 0.417 kilograms of CO₂ per kilowatt-hour, applied to twelve months of usage. Summing both and dividing by 1,000 converts kilograms into the metric tons commonly quoted.
Source:U.S. EPA greenhouse gas equivalencies
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter annual miles driven, fuel economy and monthly electricity use.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Total footprint updates instantly as you type — no button to press.
Frequently asked questions
What emission factors does this calculator use?
It uses U.S. EPA equivalency factors: about 8.887 kilograms of CO₂ per gallon of gasoline burned, and roughly 0.417 kilograms of CO₂ per kilowatt-hour of grid electricity. These are national averages, so your true figures vary with fuel type and how clean your local grid is. Regions with heavy renewable or nuclear generation emit far less per kilowatt-hour than coal-dependent grids, so treat the result as a solid estimate.
Why is my result split into driving and home energy?
Separating the two sources shows you where your emissions actually come from, which is the first step to cutting them. If driving dominates, carpooling, a more efficient vehicle, or fewer trips will help most. If home energy is larger, insulation, efficient appliances, or renewable electricity make the biggest difference. Seeing both figures side by side lets you prioritise the change that reduces the most carbon for your effort.
Does this include my whole carbon footprint?
No. This calculator covers personal driving and home electricity, two major household sources, but a complete footprint also includes flights, natural gas heating, food, goods, and public services. To capture more, add a flight emissions estimate and account for any gas or oil you burn directly. Use this figure as a strong core estimate and layer other categories on top for a fuller picture of your total impact.
How can I lower the number this shows?
The driving portion falls when you drive fewer miles or switch to a vehicle with higher fuel economy or an electric drivetrain charged on clean power. The home portion drops when you reduce electricity use through efficient lighting and appliances, better insulation, or by sourcing renewable electricity. Even modest changes, such as trimming a few thousand miles a year, move the tonnage down in a way you can measure here.
Are electric vehicles counted as zero emissions?
Not exactly. An electric vehicle produces no tailpipe emissions, so its driving figure here would be near zero if you enter it as such, but the electricity it uses still shows up in your home energy total if you charge at home. The cleanliness of your grid then determines its real footprint. On a renewable-heavy grid an EV is very low carbon; on a coal grid it is cleaner than petrol but not zero.