C14 Age From Activity Calculator
Closed-system exponential C14 age with explicitly supplied half-life and independently background/fractionation/reference-normalized activity; >1 gives signed modern age, not calendar calibration or conventional Libbyage unless caller selects 5568. Caller independently establishes sample/context/calibration applicability; not definitive chronology, provenance, taxonomy, disease or human identity.
Description
Radiocarbon activity supports an exponential age under a chosen half-life convention.
Radiocarbon activity supports an exponential age under a chosen half-life convention.1
An uncalibrated activity age is distinct from a calendar date. Use C14 Age From Activity Calculator to evaluate the supplied inputs under the model explained below.
When to use C14 Age From Activity Calculator
Use C14 Age From Activity Calculator to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.
How to use C14 Age From Activity Calculator and understand its results
- Establish the units, measurement scope and model assumptions before entering values.
- Enter Independently normalized fraction modern activity, Caller decay half life years using the field table and validation rules below, then run the tool.
- Read Uncalibrated exponential age years; interpret the units, signs, ordering and unknown-value placeholders described below.
- Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| independentlyNormalizedFractionModernActivity | Independently normalized fraction modern activity | number | Required; constraints below |
| callerDecayHalfLifeYears | Caller decay half life years | number | Required; constraints below |
Enter positive normalized fraction-modern activity and positive caller half-life in years. Return −halfLife/ln2×ln(activity). Activity above 1 is accepted and yields a negative exponential age; zero activity is rejected rather than reported as infinite age. No installed half-life, reservoir correction, isotope normalization or calendar calibration occurs.
uncalibratedAgeYears=−callerHalfLife×ln(fractionModern)/ln2 Use the field order, units and branch conditions described above.
| Output field | Meaning | Value type |
|---|---|---|
| uncalibratedExponentialAgeYears | Uncalibrated exponential age years | number |
{
"input": {
"independentlyNormalizedFractionModernActivity": 0.5,
"callerDecayHalfLifeYears": 5730
},
"output": {
"uncalibratedExponentialAgeYears": 5730
}
}Limitations and assumptions
An uncalibrated activity age is distinct from a calendar date. Apply the exact scope and assumptions explained above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.
Alternative or Complementary methods
Use IntCal Calibration Curve Lookup for a related task: Radiocarbon calibration relates calendar years to reference radiocarbon ages and uncertainties.
Use Archaeomagnetic Date Lookup for a related task: Archaeomagnetic matching compares directions under a common frame and dated reference.
References
-
C14 Age From Activity Calculator — tool.io
Similar or alternative tools
- IntCal Calibration Curve Lookup
Radiocarbon calibration relates calendar years to reference radiocarbon ages and uncertainties.
- Archaeomagnetic Date Lookup
Archaeomagnetic matching compares directions under a common frame and dated reference.