Carbon Footprint Calculator
Estimate your annual carbon footprint from electricity, natural gas, gasoline and air travel using US-average emission factors. Calculates in your browser.
Annual footprint
-
Show the math
Each source is multiplied by its emission factor and added up:
CO₂ = Σ (activity × emission factor)
Factors used: 0.3497 kg CO₂e/kWh electricity (US grid average, EPA eGRID2023), 5.306 kg/therm natural gas and 8.887 kg/gallon gasoline (EPA), 0.1355 kg CO₂e/passenger-mile flying (UK DESNZ 2025 international average, without non-CO₂ effects). All math runs in your browser.
What this does
A carbon footprint calculator estimates your annual CO₂ emissions from electricity, natural gas, gasoline, and air travel using US-average emission factors.
How to use it
- Enter your electricity and gas use.
- Enter gasoline used.
- Add flight miles.
- Read the annual CO₂ total.
How it works
Factors: electricity 0.3497 kg/kWh (US grid average, EPA eGRID2023), gas 5.306 kg/therm, gasoline 8.887 kg/gallon (EPA), flying 0.1355 kg/passenger-mile (UK DESNZ 2025 international average). Treat the total as a ballpark.
CO₂ = Σ (activity × emission factor)
Understanding your result
The total is a ballpark built on US-average emission factors, so treat it as a guide for spotting your biggest sources rather than a precise audit. For most households flying, driving, and home heating dominate, so use the breakdown to prioritize the few high-impact changes that actually move the number rather than many tiny ones.
Example
Burning 500 gallons of gasoline a year adds about 4.4 metric tons of CO₂.
Last updated .
Frequently asked questions
How is a carbon footprint calculated?
Each activity is multiplied by an emission factor and summed: electricity 0.3497 kg/kWh, gas 5.306 kg/therm, gasoline 8.887 kg/gallon, flying 0.1355 kg/passenger-mile.
Are these factors exact?
They are US-average estimates. Your grid mix, vehicle and flight type change the real numbers, so treat the total as a ballpark.
Is my data stored?
No. Everything is calculated locally in your browser.
Related tools
Wind Turbine Output Calculator
Estimate a wind turbine’s power and energy output from rotor diameter, wind speed and power coefficient using the wind power equation. Calculates in your browser.
Solar Panel Calculator
Size a solar array from your daily energy use, peak sun hours and panel wattage, get the kW needed, panel count and expected production. Calculates in your browser.
Solar Payback Calculator
Work out how long a solar system takes to pay for itself from its cost, incentives, production and electricity rate, plus lifetime savings and ROI. Calculates in your browser.
Battery Storage Calculator
Size a battery bank from daily energy use and days of autonomy, allowing for depth of discharge and round-trip efficiency. Gives kWh and amp-hours. Calculates in your browser.