Half-Life Calculator
Compute the remaining amount of a substance after a given time, or the elapsed time, from its half-life using N = N₀·(½)^(t/T½).
Input Data
Mode
N0
Half
T
Results
25
Remaining N = N₀·(1/2)^(t/T½) = 100·(1/2)^(10/5) = 25.0000.
At a glance:Half-life decay follows N = N₀·(½)^(t/T½). Given N₀, T½ and t you can find the remaining amount, or reverse to find the elapsed time. It is complementary to the mole calculator.
Formula
N = N₀·(½)^(t/T½).
t = T½·log₂(N₀/N).
How to Use
- Select the mode and enter the values.
- The tool gives the remaining amount or the elapsed time.
Case Studies
N₀=100, T½=5, t=10 → 25
Two half-lives: 100 → 50 → 25.
FAQ
What time unit?
It only needs to match T½.
What are the applications?
Radioactivity, drug metabolism.
Precision?
4 decimal places.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.