Elemental calcium is a term used on dietary supplement labels to refer to the amount of calcium in a product. Calcium pills contain calcium in a variety of molecules, such as calcium carbonate, calcium citrate, calcium citrate-maleate, etc. Each pill supplies a different amount of elemental calcium. For example, calcium carbonate is 40% elemental calcium by weight and calcium citrate is about 20%. Thus a 500 mg pill of calcium carbonate contains 200 mg of calcium and the container will indicate each pill has 200 mg of elemental calcium. This is the actual calcium content.