How Can I Measure Carbon Dioxide Emitted to the Atmosphere through my Activities (Carbon Footprint, Carbon Calculators)?

To answer this question of how much carbon dioxide is emitted to the atmosphere through your activities, you can calculate your carbon footprint by using an online Carbon Footprint Calculator (see below for description and examples). These calculators add up the carbon dioxide produced by your different personal activities, and provide you with an estimate of your annual carbon dioxide emissions.

Carbon calculators will first ask where you live, because certain emissions are related to where you live – particularly in terms of what mix of fossil fuels are used to generate your electricity. There are two major ways that carbon calculators make the calculation of your carbon footprint, either:

  1. they ask for very specific information (so you need to gather some data) – such as on how much electricity and gas/oil/wood/coal you use, how many miles you drive, how often you eat meat, how much you travel and by what means, etc.; or
  2. they ask what kind of dwelling you live in (single family home, apartment, etc. to make estimates from geographic averages); how many and what type of car you drive, how often you take public transportation and for how many miles; and ask about some of your habits. Many of the calculators that use averages are asking about behaviors or habits that would either increase your ‘footprint’ above the average, or decrease it below the average.

The variety of calculators provide more or less accuracy depending on the detail they use and what they consider. One major difference in calculators is that some do not include activities that may have a large impact on your carbon footprint, such as eating habits (whether you eat much meat - the production of meat has a high carbon footprint) or whether you travel by airplane (traveling by plane has a high carbon footprint).

Here are several free internet-based carbon footprint calculators:

I. The Environmental Protection Agency has an explanation and a calculator from their webpage at EPA offers a calculation based on your own household data, so you need to do some up front data gathering. Here’s ( how they begin:

“ 1. To get the most accurate results, gather your recent electric, gas, and/or oil bills so you can use real numbers for your household’s energy consumption. Remember that your energy bills vary by season, so use an average of winter and summer values if you can.

2. Allow yourself 10-15 minutes to enter the data.

3. After entering data, use the TAB key to continue moving through each section of the calculator. When you get to the end of a section, click “Next Section” to move on.

4. Visit the What You Can Do section of the climate change website to learn about other actions you can take to reduce your greenhouse gas emissions.”

EPA’s calculator does not ask about travel habits (such as flying) nor food and diet, which many other calculators use. EPAs webpages do provide some tips on things you can do to reduce your emissions.

II. An organization indicating it is the web’s leading carbon footprint calculator can be found at

This calculator uses factors sourced from a diverse group of references including the UK Department for Environment, Food and Rural Affairs, UK Vehicle Certification Agency, World Resource Institute, US Environmental Protection Agency, US Department of Energy, Australia Green House Office , and Canada Standards Association GHG Registries.

Choosing your country allows you to compare your carbon footprint with the average person in your country, and also sets up the units used in the calculator. The accuracy of electricity generation emissions, and gas & electricity prices, depends on where you live.

This calculator uses your home heating and electricity data, air travel information, car, motorbike, bus & rail travel habits, and includes a category for secondary information. The secondary information gives some insight into lifestyle choices that can make a difference including: food preferences, furniture, fashion, packaging, recycling, recreation, car manufacture, and finance.

The results page for this website includes a comparison to world averages, an option to buy carbon offsets (see below for a description of carbon offsets) and a link to a webpage offering some tips to reduce your carbon footprint.

III. The Nature Conservancy (TNC) has a carbon footprint calculator at

The Nature Conservancy carbon footprint calculator is one that is mainly based on averages. Questions include the number of people in your home, and information on: where you live & home energy, driving & flying, foot & diet, and recycling & waste habits. This is a very simple calculator that estimates your emissions. The Nature Conservancy also offers you the opportunity to buy offsets (see below for a description of carbon offsets)
