Carbon footprint calculator
A carbon footprint measures your annual greenhouse gas emissions in metric tons of CO₂ equivalent. This calculator covers the four biggest household sources — driving.
Total annual footprint
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Driving
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Electricity
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Natural gas
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Flights
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Emission factors (EPA 2022)
| Source | Factor |
|---|---|
| Gasoline (driving) | 19.6 lbs CO₂ per gallon |
| Electricity (US avg) | 0.93 lbs CO₂ per kWh |
| Natural gas | 11.7 lbs CO₂ per therm |
| Short/medium flight | ~1,100 lbs CO₂ per round trip |
Example
Average American household (1 person):
- 12,000 miles/yr at 28 MPG → 8,400 lbs driving
- 900 kWh/mo electricity → 10,044 lbs
- 50 therms/mo gas → 7,020 lbs
- 2 flights → 2,200 lbs
Total ≈ 12.5 metric tons CO₂e
Frequently asked
What does CO₂e mean?
CO₂ equivalent (CO₂e) converts all greenhouse gases (methane, nitrous oxide, etc.) to the equivalent warming effect of CO₂. It is the standard unit for comparing emission sources.
What is the average American's carbon footprint?
The EPA estimates the US average at about 14.5 metric tons CO₂e per person per year (2022). The global average is closer to 4 metric tons.
What emission factor is used for electricity?
0.93 lbs CO₂ per kWh, reflecting the US average grid mix (EPA 2022). Cleaner grids (solar, hydro) have lower factors; coal-heavy grids are higher.
How accurate is this estimate?
This is a rough estimate using national average factors. Your actual emissions depend on your specific utility's mix, your car's exact fuel efficiency, and flight distances.
How do I share my calculation?
Click "Share with my numbers" to copy a URL with your inputs saved.