# 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.

Estimate your personal annual carbon footprint from driving, electricity, natural gas, and flights using EPA emission factors.

**Interactive version:** https://onlinecalculator.me/everyday/carbon-footprint/
**Category:** Everyday

## 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 questions

### 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.

## Sources

- [Carbon Footprint Calculator](https://www.epa.gov/ghgemissions/carbon-footprint-calculator) — U.S. Environmental Protection Agency
- [Greenhouse Gas Equivalencies Calculator](https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator) — U.S. Environmental Protection Agency

## Related calculators

- [Mileage calculator](https://onlinecalculator.me/everyday/mileage/) — Calculate your car's actual MPG from a fill-up.
- [Road trip cost calculator](https://onlinecalculator.me/everyday/road-trip-cost/) — Total fuel cost of a road trip.
- [Electricity cost calculator](https://onlinecalculator.me/everyday/electricity-cost/) — Monthly cost to run appliances at home.
- [Fuel economy converter](https://onlinecalculator.me/unit-converters/fuel-economy/) — Convert MPG to L/100km and other fuel economy units.

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