Half-Life Calculator
Calculate radioactive decay using the half-life formula. Find remaining quantity after any number of half-lives, time for decay, or the half-life itself. Free.
Half-Life Calculator
toolznova.com • Free Calculator
How to Use
Calculate radioactive decay in 3 steps.
Choose Calculation
Select what you want to find — remaining quantity, time, or half-life.
Enter Known Values
Enter the initial quantity, half-life, and time or remaining amount.
Get Answer
Click Calculate for the precise result with the formula used.
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Why Calculate Half-Life?
- Nuclear Physics: Core concept for understanding radioactive decay.
- Carbon Dating: C-14 half-life (5730 years) used to date ancient artifacts.
- Medicine: Drug half-life determines dosing intervals in pharmacology.
- Nuclear Power: Waste management requires half-life calculations.
- Safety: Determining safe exposure times near radioactive materials.
- Chemistry: First-order reaction kinetics use the same formula.
Tips & Examples
- Half-life formula: N(t) = N₀ × (1/2)^(t/t½).
- Carbon-14 half-life: 5730 years (used in archaeological dating).
- After 1 half-life: 50% remains. After 2: 25%. After 10: 0.098%.
- Drug half-life: after 5 half-lives, ~97% of drug is eliminated from body.
- Uranium-235 half-life: 704 million years — very slow decay.
- Polonium-214 half-life: 0.000164 seconds — extremely fast decay.
Free Half-Life Calculator Online
ToolzNova's free half-life calculator computes radioactive decay using the half-life formula. Find remaining quantity after time t, time required to reach a certain amount, or calculate the half-life from experimental data.
Half-life is the time required for half of a radioactive substance to decay. It applies to nuclear physics, carbon dating, drug pharmacokinetics, and any first-order decay process.
Half-Life Formula
N(t) = N₀ × (1/2)^(t/t½). Where N₀ is initial quantity, N(t) is remaining quantity, t is time elapsed, and t½ is the half-life. This can be rearranged to find t or t½ when the other variables are known.