数学

Half-Life Calculator

Calculate the half-life, initial quantity, remaining quantity, or time elapsed for a radioactive or decaying substance.

Note: Time Elapsed and Half-Life must use the same units (e.g., years, days).

Remaining Quantity
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使い方
  1. Select the variable you want to solve for from the dropdown.
  2. Enter the values for the remaining 3 variables.
  3. The calculator will instantly compute the missing variable using the standard radioactive decay formula.

計算式

Decay Formula:
N(t) = N₀ × (1/2)(t / t½)

Where:
N(t) = Remaining Quantity
N₀ = Initial Quantity
t = Time Elapsed
t½ = Half-Life

Half-life is the amount of time it takes for half of a substance (often a radioactive isotope or a medication in the bloodstream) to decay or be eliminated. The math behind half-life is an exponential decay function, meaning the substance never truly reaches zero mathematically, but becomes infinitesimally small.