At Carbonfund.org, we take every step possible to provide our donors with an accurate view of their carbon footprint. We base all of our calculations on reputable sources like the EPA, the WRI and the IPCC, and you can view the assumptions that we use for our all of our calculators any time you want online. Now, I am not just bringing this up to toot the Carbonfund.org horn, but in a voluntary industry it is important to look for carbon offset organizations that are taking the proper steps to ensure accuracy. Carbonfund.org also ensures third-party verification of projects to the highest certification standards. EcoBusiness Links just released a survey that found that over 1/3rd of flight carbon calculators are under reporting CO2 emissions — this means that people won’t fully understand their climate impact and they also won’t actually be offsetting enough to truly make their trip carbon neutral. According to independent references, a flight across the country should emit 1.81 – 2.72 metric tons CO2 per passenger. Carbonfund.org’s flight calculator produced a result of 2.41 metric tons CO2, to the middle of that range. Carbonfund.org also allows users to include radiative forcing. Check out the results of the study by clicking here to see how some companies and nonprofits compare. And use our accurate and reliable flight calculator by clicking here.