For readers who wonder about their carbon footprint, but don't know quite how to calculate the long and short of it, this Carbon Footprint Calculator from the U.S. Environmental Protection Agency (EPA) will arrive as a welcome resource. The site takes users through several steps. First, readers enter the number of people in their household, as well as their zip code. Next, they enter their average monthly bills for natural gas, electricity, fuel oil, and propane. From there, they enter the number of vehicles their household owns, and how many miles household members drive per year. Finally, readers enter how much their household recycles. At the end, the program tells users what their approximate carbon footprint is. Along the way, readers will be introduced to suggestions about how to reduce their carbon footprint.