Calcium vs. Calcium Carbonate

What's the Difference?

Calcium and calcium carbonate are both essential compounds for the human body, but they differ in their chemical composition and uses. Calcium is a chemical element with the symbol Ca and atomic number 20. It is a soft, silvery-white metal that is crucial for various bodily functions, including bone and teeth formation, muscle contraction, and nerve transmission. On the other hand, calcium carbonate is a chemical compound with the formula CaCO3. It is a white, odorless powder that is commonly found in rocks, shells, and pearls. Calcium carbonate is widely used as a dietary supplement to provide the body with calcium, as an antacid to relieve heartburn and indigestion, and as a filler in various products like paints and plastics.


AttributeCalciumCalcium Carbonate
Chemical FormulaCaCaCO3
Molar Mass40.08 g/mol100.09 g/mol
AppearanceSilvery-whiteWhite solid
State at Room TemperatureSolidSolid
Solubility in WaterPartially solubleSlightly soluble
Common UsesBuilding strong bones and teeth, nerve function, muscle contractionAntacid, dietary supplement, chalk, limestone

Further Detail


Calcium and calcium carbonate are two closely related substances that are often discussed in the context of nutrition and health. While both are important for various bodily functions, they differ in terms of their chemical composition, sources, and applications. In this article, we will explore the attributes of calcium and calcium carbonate, highlighting their similarities and differences.

Chemical Composition

Calcium is a chemical element with the symbol Ca and atomic number 20. It is an alkaline earth metal and one of the most abundant elements in the Earth's crust. Calcium carbonate, on the other hand, is a chemical compound with the formula CaCO3. It is a common substance found in rocks, shells of marine organisms, and even in eggshells.

While calcium is a pure element, calcium carbonate is a compound composed of calcium, carbon, and oxygen atoms. The carbonate ion (CO32-) gives calcium carbonate its unique properties and makes it an essential ingredient in various industries.


Calcium can be obtained from a variety of dietary sources. Dairy products such as milk, cheese, and yogurt are rich in calcium. Additionally, leafy green vegetables like kale and broccoli, as well as certain fish like salmon and sardines, are good sources of this mineral. Calcium supplements are also available for those who may have difficulty meeting their daily requirements through diet alone.

Calcium carbonate, on the other hand, is primarily sourced from natural deposits of limestone, marble, and chalk. These rocks are crushed and processed to obtain calcium carbonate in various forms, including powders, granules, and tablets. It is worth noting that calcium carbonate is also used as an antacid to relieve heartburn and indigestion.

Health Benefits

Both calcium and calcium carbonate play crucial roles in maintaining overall health and well-being.

Calcium is well-known for its importance in building and maintaining strong bones and teeth. It is a vital mineral for bone health, especially during childhood and adolescence when bone growth is at its peak. Calcium also contributes to proper muscle function, nerve transmission, and blood clotting. Furthermore, it is involved in regulating blood pressure and supporting the immune system.

Similarly, calcium carbonate provides the body with essential calcium, which is necessary for various physiological processes. It helps prevent osteoporosis, a condition characterized by weak and brittle bones, particularly in postmenopausal women. Calcium carbonate also aids in reducing the risk of colon cancer, regulating heart rhythm, and maintaining healthy teeth.

Supplementation and Absorption

Supplementation with calcium is often recommended for individuals who have difficulty meeting their daily calcium requirements through diet alone. Calcium supplements come in various forms, including calcium carbonate.

Calcium carbonate is a popular choice for supplementation due to its high elemental calcium content. It contains approximately 40% elemental calcium, meaning that a 500 mg calcium carbonate supplement provides around 200 mg of elemental calcium. However, it is important to note that calcium carbonate requires stomach acid for optimal absorption. Therefore, individuals with low stomach acid levels may have difficulty absorbing calcium carbonate effectively.

On the other hand, calcium citrate, another common calcium supplement, does not require stomach acid for absorption and may be a better option for individuals with reduced stomach acid levels.

Industrial Applications

Calcium carbonate finds extensive use in various industries due to its unique properties. One of its primary applications is in the manufacturing of cement, where it acts as a key ingredient in the production of concrete. It is also used as a filler in the paper, paint, and plastic industries, enhancing the properties of these materials.

Calcium, as a pure element, has limited industrial applications. However, it is used in the production of alloys, such as aluminum-calcium alloys, which are used in the automotive industry for lightweight construction. Calcium is also employed in the production of certain metals, including thorium and uranium, through a process called electrolysis.


Calcium and calcium carbonate are closely related substances that share many similarities but also have distinct attributes. While calcium is a pure element, calcium carbonate is a compound composed of calcium, carbon, and oxygen. Both are essential for maintaining good health, with calcium playing a crucial role in bone health, muscle function, and nerve transmission. Calcium carbonate, sourced primarily from natural deposits, is widely used in various industries, while calcium is mainly obtained from dietary sources. Understanding the similarities and differences between calcium and calcium carbonate can help individuals make informed decisions regarding their nutritional needs and supplementation choices.

Comparisons may contain inaccurate information about people, places, or facts. Please report any issues.