http://uk.oneworld.net/article/archive/8371 en_GB_uk http://uk.oneworld.net/article/view/124184/1/8371 There are lot of carbon calculators on the web. We particularly like this one produced by COIN, because it's UK-based and includes the climate implications of what we buy and what we eat. COIN also has a net dowloadable spreadsheet that will help you work it out without a calculator. Alternatively there's a more international calculator from the World Resources Institute which works well and gives results directly on the screen.