Carbon Dating Calculator
Radiocarbon age from the fraction of carbon-14 left.
Work out Carbon Dating. Radiocarbon age from the fraction of carbon-14 left. Says where the method stops being reliable.
As a percentage of the level in a living sample. 100% means modern.
5,730 years is the Cambridge value. Older literature uses Libby's 5,568 — worth matching whichever a source quotes.
Radiocarbon age
11,460 years
2 half-lives of decay
This is a raw radiocarbon age, not a calendar date. Atmospheric carbon-14 has not been constant — it varies with solar activity, and fossil fuel burning and atmospheric weapons testing both shifted it sharply in the twentieth century. Published dates are run through a calibration curve such as IntCal20 to convert this figure into calendar years, and the correction can run to several centuries. The method also runs out at roughly 50,000 years, by which point too little carbon-14 is left to count reliably.
How the Carbon Dating Calculator works
Give the percentage of carbon-14 still present relative to a living sample and this returns the radiocarbon age. It also shows the same sample dated with Libby's original half-life, because older literature uses 5,568 years where modern work uses 5,730 and the two differ by about 3%.
Also known as: radiocarbon dating calculator · carbon 14 calculator · how old is a sample · c14 age calculator
Frequently asked questions
How does carbon dating work?
Living things exchange carbon with the atmosphere, so their carbon-14 matches atmospheric levels. That exchange stops at death and the carbon-14 decays with a half-life of 5,730 years. Measuring how much is left dates the death.
What is the limit of carbon dating?
Around 50,000 years, roughly nine half-lives, by which point under 0.2% of the original carbon-14 remains and counting it accurately becomes impractical. Older material needs a different isotope system such as potassium-argon or uranium-lead.
Why do published dates differ from this calculation?
Because atmospheric carbon-14 has not been constant. Real dates are calibrated against tree rings and other dated records using a curve such as IntCal20, and the correction can shift a date by several centuries. This page gives the uncalibrated radiocarbon age.
Can carbon dating be used on rocks?
No. It only works on material that was once alive and exchanging carbon with the atmosphere — bone, wood, charcoal, shell, textiles. Rocks are dated with isotope systems that have much longer half-lives.
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