How Fast Is Coral Growth?

Reef-building corals lay down their calcium carbonate skeletons at 1-2 cm per year. The Great Barrier Reef has been building for an extraordinarily long span, and individual coral heads in some Caribbean reefs are thousands of years old.

Despite their slow growth, coral reefs support roughly a quarter of all marine species.

• Roughly 3× faster than fingernails grow
• About 20,000× slower than bamboo grows