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Calcium vs. Calcium Carbonate: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Published on November 18, 2023
Calcium is a chemical element with the symbol Ca, while calcium carbonate is a compound made up of calcium, carbon, and oxygen with the formula CaCO₃.

Key Differences

Calcium is an essential chemical element found in various foods, vital for maintaining bone health and carrying out numerous body functions. Calcium carbonate, on the other hand, is a naturally occurring compound derived from calcium, often found in rocks and used in antacids and dietary supplements.
While calcium serves as an important ion in our body, participating in muscle function, nerve transmission, and intracellular signaling, calcium carbonate is often used to supplement the intake of calcium, especially when natural dietary consumption is inadequate.
Calcium can be found in various forms, such as calcium citrate, calcium lactate, and calcium gluconate, based on the substance it's combined with. Calcium carbonate is one such compound, recognized for its high calcium content and its utility in products like chalk, lime, and limestone.
The consumption of calcium is vital for individuals of all ages, ensuring healthy bones and teeth. Calcium carbonate serves as a common source of calcium supplementation, beneficial for those who might not get enough calcium from their diet.
Calcium plays a pivotal role in coagulation and is a significant component of our bones and teeth. Calcium carbonate, being alkaline, is used to neutralize acidic conditions in soils and water and is a primary component of many shells and structures of marine organisms.

Comparison Chart


Chemical element
Chemical compound



Primary Use

Vital for bone health, muscle function, nerve transmission
Dietary supplement, antacid, component in rocks


Found in various compounds and foods
Naturally found in the form of rocks like limestone


Element that is part of various compounds
One specific compound containing calcium, carbon, and oxygen

Calcium and Calcium Carbonate Definitions


A chemical element with the symbol Ca and atomic number 20.
Milk is a good source of calcium.

Calcium Carbonate

A source of calcium used in dietary supplements.
Some people take calcium carbonate tablets to supplement their dietary calcium intake.


A soft, gray, alkaline earth metal.
Calcium is essential for building strong bones.

Calcium Carbonate

A compound with the chemical formula CaCO₃.
The main component of eggshells is calcium carbonate.


An essential nutrient for living organisms.
Calcium deficiency can lead to weak bones.

Calcium Carbonate

A base that can neutralize acids.
Calcium carbonate is used to counteract overly acidic soil.


A cation that plays a crucial role in biological processes.
Calcium ions are vital for muscle contraction.

Calcium Carbonate

A primary component in many marine organism shells.
Coral reefs are largely made up of calcium carbonate.


A metal used in various industrial processes.
Calcium is used as a reducing agent in the extraction of other metals.

Calcium Carbonate

A white, chalky compound that occurs naturally in limestone.
Calcium carbonate is used in antacids to relieve heartburn.


A silvery, moderately hard alkaline-earth metal that constitutes approximately 3.6 percent of the earth's crust and is a basic component of most animals and plants. It occurs naturally in limestone, gypsum, and fluorite, and its compounds are used to make plaster, quicklime, Portland cement, and metallurgic and electronic materials. Atomic number 20; atomic weight 40.08; melting point 842°C; boiling point 1,484°C; specific gravity 1.54; valence 2. See Periodic Table.


The chemical element (Symbol Ca), with an atomic number 20. It is a soft, silvery-white alkaline earth metal which occurs naturally as carbonate in limestone and as silicate in many rocks.


(countable) An atom of this element.


An elementary substance; a metal which combined with oxygen forms lime. It is of a pale yellow color, tenacious, and malleable. It is a member of the alkaline earth group of elements. Atomic weight 40. Symbol Ca.


A white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals


Is calcium carbonate a natural substance?

Yes, calcium carbonate naturally occurs in substances like limestone.

Can you get calcium from calcium carbonate supplements?

Yes, calcium carbonate supplements are a common source of calcium intake.

What is calcium primarily used for in the body?

Calcium is primarily used for bone formation and maintaining bone strength.

How is calcium carbonate different from calcium?

Calcium is a chemical element, while calcium carbonate is a compound containing calcium, carbon, and oxygen.

How does calcium benefit muscles?

Calcium plays a pivotal role in muscle contraction and relaxation.

Why is calcium carbonate used in agriculture?

It's used to neutralize acidic soil, enhancing soil quality.

Why might someone take a calcium carbonate antacid?

Calcium carbonate antacids can help neutralize stomach acid and relieve heartburn.

What foods are rich in calcium?

Foods like milk, cheese, yogurt, and leafy greens are rich in calcium.

What is the role of calcium in nerve function?

Calcium aids in transmitting signals between nerve cells.

Are there side effects to consuming too much calcium carbonate?

Yes, excessive consumption can lead to kidney stones, constipation, and impaired absorption of other minerals.

Can you find calcium carbonate in everyday products?

Yes, it's found in antacids, dietary supplements, and even some baking powders.

Does calcium carbonate dissolve in water?

Calcium carbonate is poorly soluble in water but can dissolve in acid.

Why is calcium important for children?

Calcium is crucial for the growth and development of strong bones in children.

Can calcium carbonate be used in food?

Yes, it's often used as a food additive or preservative.

How do our bodies absorb calcium?

The body absorbs calcium in the intestines, aided by vitamin D.

Where is calcium carbonate most commonly found in nature?

It's most commonly found in rocks like limestone and marble.

Are there other compounds of calcium besides calcium carbonate?

Yes, examples include calcium citrate, calcium phosphate, and calcium chloride.

Why is calcium carbonate added to toothpaste?

It's used as a mild abrasive to help remove plaque and stains.

Is calcium a metal or non-metal?

Calcium is a metal, specifically an alkaline earth metal.

What happens if the body has too little calcium?

A deficiency can lead to weakened bones, muscle cramps, and in severe cases, rickets.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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