There are a host of calculators out there to help you or your office determine your impact. Once your impact is known then create a goal of how you would like to reduce it. Here are a few of my favorites to get you started:
Global Footprint Network: A good overall calculator on general green footprint
Household Savings Calculator: Developed by the NRDC to track home energy savings
Water Calculator: Developed by H2O Conserve this measures water consumption.
Xerox Sustainability Calculator: A great calculator that measures the overall impact a company’s printers and copiers have on the environment.