Every living thing on earth contains the element carbon. When an organism dies, be it a plant or an animal, the carbon acquired during its lifetime begins to decay at a steady, predictable rate, releasing carbon-14, a radioactive isotope with a half-life of 5,730 years. By measuring the amount of carbon-14 left in the organism, scientists can estimate how long ago the organism died. Radiocarbon dates are often reported as a range.

In recent years, scientists have refined methods for radiocarbon dating. Accelerated mass spectrometry, or AMS, is more precise than standard radiocarbon dating and can be performed on smaller samples.

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Radiocarbon Dating is an "ArchaeInteractive" module from North Carolina State University.