Chronology & Dating
Radiocarbon calibration, potassium-argon dating, thermoluminescence age estimation, and converting between BP and BCE/CE date formats: absolute and relative dating methods for researchers who already have raw lab measurements and need the standard calibration applied.
Calculators & Tools
BP to BCE/CE Converter
The BP to BCE/CE Converter turns a years-before-present figure into a calendar year and back again, correctly subtracting 1949 rather than 1950 when a date crosses into BCE, since the Gregorian calendar has no year zero. It also includes an optional marine reservoir (delta-R) adjustment for converting shell and marine sample dates.
Radiocarbon Calibration Calculator
The Radiocarbon Calibration Calculator works out the conventional radiocarbon age from a lab-reported percent modern carbon or delta-14C measurement, using the standard Libby half-life convention. It also applies the marine reservoir correction (delta-R) needed for shell and marine samples, and converts a calibrated cal BP figure into a BCE or CE calendar year.
Potassium-Argon Dating Calculator
The Potassium-Argon Dating Calculator works out a K-Ar age from measured argon-40 and potassium-40, using the Steiger and Jager (1977) IUGS-recommended decay constants. It corrects raw argon-40 measurements for atmospheric contamination using measured argon-36, flags samples with a low radiogenic percentage, and explains the excess argon problem that can push ages older than the true value.
Bayesian Age-Depth Model Calculator
The Age-Depth Model Calculator interpolates the estimated calibrated age at any depth in a sediment or stratigraphic core from your dated control points, and automatically flags age reversals that would otherwise distort a chronology. It also explains what full Bayesian, Bacon-style modeling adds beyond simple linear interpolation, and reports a simplified uncertainty estimate alongside the interpolated age.
Thermoluminescence Age Estimator
The Thermoluminescence Age Estimator calculates a TL age by dividing equivalent dose by total dose rate, correctly weighting the alpha radiation component by its material-specific efficiency (a-value) before combining it with beta, gamma, cosmic, and internal dose rates. It also applies the standard Zimmerman burial water content correction, two steps that simple dose-rate sums commonly skip.