C:N Ratio Diet Indicator

Convert measured C/N mass percentages to atomic ratio and caller collagen-preservation screen; this ratio is not a diet determination.

Description

Carbon-to-nitrogen mass ratio differs from atomic C/N because the elements have different atomic masses.

Carbon-to-nitrogen mass ratio differs from atomic C/N because the elements have different atomic masses. A caller's preservation band can screen the atomic ratio without determining diet.^[1]

Convert measured C/N mass percentages to atomic ratio and caller collagen-preservation screen; this ratio is not a diet determination.

When to use C:N Ratio Diet Indicator

Use this tool to convert measured C/N mass percentages to atomic ratio and caller collagen-preservation screen; this ratio is not a diet determination.

Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.

How to use C:N Ratio Diet Indicator and understand its results

Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.
Enter carbonMassPercent, nitrogenMassPercent, carbonAtomicMass, nitrogenAtomicMass, callerAtomicRatioBounds using the field table and calculation rules, then run the tool.
Read atomicCarbonNitrogenRatio, withinCallerPreservationBand. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
carbonMassPercent	Carbon mass percent	number	Required
nitrogenMassPercent	Nitrogen mass percent	number	Required
carbonAtomicMass	Carbon atomic mass	number	Required
nitrogenAtomicMass	Nitrogen atomic mass	number	Required
callerAtomicRatioBounds	Caller atomic ratio bounds	list of number	Required

Enter nonnegative carbon percentage, positive nitrogen percentage and positive supplied atomic masses. C plus N cannot exceed 100 percent. Supply two ordered nonnegative atomic-ratio bounds. Return the converted atomic ratio and a boolean true for inclusive band membership.

atomicC/N = (carbonMassPercent/atomicMassC)/(nitrogenMassPercent/atomicMassN)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
atomicCarbonNitrogenRatio	Atomic carbon nitrogen ratio	number
withinCallerPreservationBand	Within caller preservation band	boolean

json

{
  "input": {
    "carbonMassPercent": 36,
    "nitrogenMassPercent": 12,
    "carbonAtomicMass": 12,
    "nitrogenAtomicMass": 14,
    "callerAtomicRatioBounds": [
      3,
      4
    ]
  },
  "output": {
    "atomicCarbonNitrogenRatio": 3.5,
    "withinCallerPreservationBand": true
  }
}

Limitations and assumptions

The band is supplied rather than a universal collagen-quality rule. A compatible ratio alone does not establish collagen integrity, reliable dating or dietary composition.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Bone Collagen Yield Percent Checker: Calculate blank-corrected dry-bone collagen yield and compare caller QC threshold, preserving negative blank-corrected nondetections; yield alone does not establish collagen integrity or reliable dating. For a complementary task, use Delta13C C3/C4 Diet Mix: Solve a caller two-endmember linear delta13C diet scenario with explicit tissue offset; assumes equal carbon routing and consistent isotope basis, not identified foods or an actual diet diagnosis.

References

C:N Ratio Diet Indicator — tool.io

Similar or alternative tools

Bone Collagen Yield Percent Checker
Calculate blank-corrected dry-bone collagen yield and compare caller QC threshold, preserving negative blank-corrected nondetections; yield alone does not establish collagen integrity or reliable dating.
Delta13C C3/C4 Diet Mix
Solve a caller two-endmember linear delta13C diet scenario with explicit tissue offset; assumes equal carbon routing and consistent isotope basis, not identified foods or an actual diet diagnosis.