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Radiometric Dating Age from Isotope Ratio Calculator

t = ln(N₀/N) / λ — age from remaining fraction.

Calculates the age of a sample from the remaining fraction of parent isotope: t = ln(N₀/N) / λ = t½ × ln(N₀/N) / ln 2. Supports ¹⁴C, ²³⁸U, ⁴⁰K via user-entered half-life.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

t = t½ · ln(N₀/N) / ln 2

In depth

Calculates the age of a sample from the remaining fraction of parent isotope: t = ln(N₀/N) / λ = t½ × ln(N₀/N) / ln 2. Supports ¹⁴C, ²³⁸U, ⁴⁰K via user-entered half-life.