One of the best is the University of California at Berkeley’s Cool Climate Calculator. A free web-based tool. Takes into account daily driving mileage, grocery, and electricity expenses, assigns a carbon score that you can compare to similar households across the 28 largest urban areas in the United States.

Another great carbon footprint calculator is available at EarthLab.com. Consists of a three minute survey which gives you a carbon footprint score. This score can be saved and updated as you work on reducing your impact.

CarbonFund.org allows you to assess your carbon footprint and then offers you the ability to offset such emissions by investing in clean energy initiatives.

Other Carbon Footprint Calculators

1. CarbonFootprint.com
2. CarbonCounter.org
3. Conservation International
4. The Nature Conservancy
5. British Oil Giant BP