Exponential Decay Calculator
A = A₀ · e^(-kt). Compute remaining quantity, half-life, or decay constant.
Result
A at t = 14
49.658530
Half-life: 13.8629 time units.
- Fraction remaining49.66%
- Half-life13.8629
- Half-lives elapsed1.0099
- Decay constant k0.0500
Step-by-step
- A = 100 × e^(−0.05 × 14) = 100 × e^(−0.7000000000000001) = 100 × 0.496585 = 49.658530.
- Half-life = ln(2) / k = 0.6931 / 0.05 = 13.8629.
How to use this calculator
- Enter the initial amount, decay constant k, and elapsed time t.
- Read the remaining amount and half-life.
About this calculator
Exponential decay: A = A₀e^(-kt), with k > 0. Models radioactive decay, drug clearance, capacitor discharge, and any process where the decay rate is proportional to the remaining amount. Half-life — time for half to decay — equals ln(2)/k regardless of starting amount.
Frequently asked
t½ = ln(2)/k ≈ 0.693/k. So if you know t½, k = ln(2)/t½.
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