Radiocarbon Age Calculator (Carbon-14 Dating)
Conventional radiocarbon age from the share of carbon-14 left in a sample, and the age with the modern half-life.
Results
The dashed line marks the value you entered.
What this tool does
By international convention, radiocarbon ages are reported with Libby's original half-life of 5568 years (a mean life of 8033 years) and counted back from 1950, even though the true half-life is about 5730 years — so labs and papers stay comparable. That conventional age is not yet a calendar date: the amount of carbon-14 in the air has varied over time, and the age must be calibrated against a curve such as IntCal20, which can move it by centuries. Beyond about 50 000 years so little carbon-14 is left that the method stops working.
Formula
conventional age = −8033 × ln(F) (Libby mean life, years before 1950) · with 5730 years: −8267 × ln(F)
Variables
| Symbol | Meaning | Unit |
|---|---|---|
fm | Carbon-14 left (percent modern carbon) | % |
A | Conventional radiocarbon age (years BP) | a |
AT | Age with the modern half-life (5730 years) | a |
HL | Libby half-lives elapsed | — |
Worked example
- Carbon-14 left (percent modern carbon)50 %
- Conventional radiocarbon age (years BP)5568 a
- Age with the modern half-life (5730 years)5730 a
- Libby half-lives elapsed1.000
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.