The Common Carbon Metric (CCM) is a protocol developed by the United Nations Environment Program's Sustainable Buildings & Climate Initiative (UNEP-SBCI) for measuring energy use and reporting greenhouse gas (GHG) emissions from building operations.

Its purpose is to support GHG emissions reductions through accurate measurement of energy efficiency. It is a universal method of measuring a building's carbon footprint and allows emissions from buildings around the world to be consistently assessed and compared.

Therefore, it is used for assessing the carbon footprint of building operations around the world.