Free Radioactive Decay Calculator
Calculate remaining radioactive material using N = N0 * (1/2)^(t/t_half).
g
years
years
Remaining Amount
25.0000 g
Amount Decayed75.0000 g
Fraction Remaining0.250000
Remaining Amount vs Time Elapsed
Radioactive Decay
Radioactive materials decay at a rate characterized by the half-life.
Formula
N = N_0 * (1/2)^(t / t_half)
where N_0 is the initial amount, t is elapsed time, and t_half is the half-life. After each half-life, exactly half the material remains.
Example Calculation
100 g of Carbon-14 (half-life 5730 years) after 11,460 years (2 half-lives).
- 01N = N0 * (1/2)^(t/t_half)
- 02N = 100 * (1/2)^(11460/5730)
- 03N = 100 * (1/2)^2
- 04N = 100 * 0.25 = 25 g
- 05Decayed: 100 - 25 = 75 g
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