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.

Enter your annual totals.

Annual footprint

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Electricity-
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Gasoline-
Air travel-

Show the math

Each source is multiplied by its emission factor and added up:

CO₂ = Σ (activity × emission factor)

Factors used (US averages): 0.417 kg/kWh electricity, 5.3 kg/therm gas, 8.89 kg/gallon gasoline, 0.18 kg/passenger-mile flying. 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

  1. Enter your electricity and gas use.
  2. Enter gasoline used.
  3. Add flight miles.
  4. Read the annual CO₂ total.

How it works

Factors are US averages: electricity 0.417 kg/kWh, gas 5.3 kg/therm, gasoline 8.89 kg/gallon, flying 0.18 kg/passenger-mile. 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 prioritise 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 tonnes of CO₂.

Sources & methodology

Last updated .

Frequently asked questions

How is a carbon footprint calculated?

Each activity is multiplied by an emission factor and summed: electricity 0.417 kg/kWh, gas 5.3 kg/therm, gasoline 8.89 kg/gallon, flying 0.18 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.