Calcium dosages are measured in milligrams (mg). Supplements may contain anywhere from 100 to 2000mg of calcium per serving. It's a good idea to begin your search by focusing on the products that offer the right amount of calcium for your needs. Then, you can compare the forms available and choose the one that will be the easiest for you to take. Manufacturers offer calcium supplements in tablet, capsule, softgel, caplet, liquid, gummies, chewable and powder forms. Slow release formulas that gradually release small amounts of calcium over an extended period of time are available in addition to conventional options.