There are lots of carbon calculators, with different tradeoffs between user experience, comprehensiveness and underlying assumptions.
Calculators that only cover direct household energy and transportation emissions miss the indirect emissions associated with what you buy. Those calculators calculate your “carbon toeprint”, not your footprint. The US EPA calculator is a toeprint calculator. It covers household energy, driving, and recycling but not public transit, flying, food, goods or services.
My favorite calculator is the Cool Climate Calculator. It has the best combination of usabiity and actionable results.
To use the CoolClimate calculator you’ll need to estimate how many miles you drive or use public transportation and how many air trips your household takes. You’ll need your energy and water bills, an estimate of the amounts of different foods your household uses, and your monthly budget for different goods and services.
Use the information buttons in the calculator to learn more or choose the simple or advanced versions of each category to customize for your family. Because of the way we track spending at our house, it’s easier for us to use the advanced versions in each category. Use whatever works best for you.
Your results will be compared to similar households in your location, which is a more useful comparison than a generic national average. Every region has a different energy mix, climate, and public transportation system which shifts the average carbon footprint for that location.
The results are displayed in a chart that lets you see which categories account for the most carbon equivalent emissions in your lifestyle.
Which categories are quantitatively most important in your household? For most American’s it’s home energy use and transportation.