Radiocarbon Dating (Carbon-14) Age Calculator
Radiocarbon dating calculates the chronological age of carbonaceous organic artifacts (wood, bone, charcoal, peat) by measuring residual Carbon-14 (¹⁴C) radioactivity relative to modern atmospheric equilibrium. Developed by Willard Libby (Nobel Prize in Chemistry, 1960), the exponential decay law (N(t) = N₀ · e^(-λt)) provides the universal timeline for archaeology, paleontology, and Quaternary geochronology.
Measured percentage of ¹⁴C relative to modern pre-industrial reference standard (100% = modern)
Standard radiocarbon reference datum year (1950 CE = 0 BP by international convention)
Conventional radiocarbon age in years Before Present (relative to 1950 CE datum)
How to Use This Calculator
- Enter the measured percentage of modern Carbon-14 remaining in the specimen.
- Verify the standard reference year (default 1950 CE for BP reporting).
- Inspect the conventional radiocarbon age in Years BP.
- Review the converted calendar date (BCE/CE), half-lives elapsed, and archaeological epoch.
Formula & Calculation Methodology
Carbon-14 decays exponentially with a Libby mean-life of 8,267 years (half-life t½ = 5,730 years; decay constant λ = ln(2)/5730 ≈ 0.00012097 yr⁻¹). The age t represents elapsed years since biological death halted metabolic carbon exchange with the biosphere.
Worked Example
Neolithic charcoal sample retaining exactly 50% of its initial Carbon-14 content
Frequently Asked Questions
Why is the radiocarbon dating datum fixed at 1950 CE?↓
By international convention established by Hessel de Vries and Willard Libby, 'Present' is permanently fixed at 1950 CE to prevent the baseline from shifting every year and because mid-20th century atmospheric nuclear bomb testing doubled global ¹⁴C levels, contaminating natural baseline equilibrium.
How does living organic matter replenish Carbon-14?↓
Cosmic rays bombard upper atmospheric nitrogen (¹⁴N + n → ¹⁴C + p), creating ¹⁴C which oxidizes to ¹⁴CO₂. Living plants absorb it via photosynthesis, and animals consume plants. When an organism dies, metabolic intake ceases, and ¹⁴C begins its unreplenished radioactive decay.
What is the difference between conventional radiocarbon years and calibrated calendar years?↓
Atmospheric ¹⁴C production has fluctuated historically due to solar solar modulation and Earth's magnetic field changes. To convert conventional BP years into true solar calendar years, researchers cross-calibrate against tree rings (dendrochronology) using the IntCal calibration curves.
What is the maximum practical age limit of radiocarbon dating?↓
Because Carbon-14 has a half-life of 5,730 years, less than 0.2% of ¹⁴C remains after 50,000 years (roughly 8 to 9 half-lives). Beyond 50,000 BP, remaining radioactivity drops below background detector noise thresholds, requiring longer-lived isotopes like Potassium-Argon or Uranium-Thorium.
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Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.