@kymatahealth: Same 500 mg on the label, 200 mg or 105 mg of calcium The calculator on our calcium page multiplies the compound weight by the share that is calcium: 500 mg of calcium carbonate × 40% is 200 mg of calcium, and 500 mg of calcium citrate × 21% is 105 mg. Supplement Facts panels list the calcium itself; the front of some bottles gives the compound weight. Arithmetic only, not a recommendation. Free at kymatahealth.com. Free educational tool, not medical advice. #calcium #supplements #labelreading