Estimate the age of a sample from its remaining carbon-14 fraction and the half-life. For archaeology, geology and paleontology (organic material only).
由剩余碳-14 比例推算样品年代。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Radiocarbon dating | t = (T₁/₂/ln2)·ln(A₀/A) | Libby 1949 |
| C-14 half-life | 5730 ± 40 yr (Libby 5568 old) | Stuiver & Polach 1977 |
| Modern standard | 1950 atmosphere as modern standard | Radiocarbon convention |
| Calibration | IntCal20 calibration curve | IntCal20 |
| Dating limit | ≈50 000 yr (≈9 half-lives) | Dating limits |
| Delta notation | Δ14C per-mille deviation | S&P 1977 |
Nuclear data used on this page and their authoritative sources, for verification and citation
| Constant | Value | Unit | Source |
|---|---|---|---|
| 14C "Cambridge" half-life | 5730 ± 40 | a | Godwin 1962, internationally used physical value |
| 14C "Libby" conventional half-life | 5568 | a | Stuiver & Polach 1977 (Radiocarbon) convention |
| Natural logarithm of 2, ln 2 | 0.6931471805599453 | — | Mathematical constant (exact) |
| Avogadro constant N_A | 6.02214076e23 | mol⁻¹ | SI defining constant (exact) |
Note: radiocarbon dating still uses the Libby value of 5568 a as a convention for consistency with historical data, while the physical half-life is 5730 ± 40 a; this page uses 5730 a. Reported ages further require δ¹³C correction and calibration against the IntCal curve.