Exponential Decay Calculator
A = A₀ · e^(-kt). Compute remaining quantity, half-life, or decay constant.
Result
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
How is k related to half-life?+
Why is half-life independent of starting amount?+
What's a real-world example?+
Is decay always exponential?+
Can the calculator handle drug clearance?+
Related calculators
More tools you might like
Hand-picked tools that pair well with this one — same audience, same intent.
A = A₀ · e^(kt) for continuous growth, or A = A₀ · (1 + r)^t for discrete.
log_b(x) for any base b > 0, b ≠ 1, x > 0. Common bases shown side-by-side.
b^x — the inverse of a logarithm. Given the log value and base, recover the original number.
A = P · e^(rt) — the limit of compound interest as the compounding frequency → ∞.
b^x — supports fractional, negative, and zero exponents.
Future value of an investment growing with compound interest plus monthly contributions, with a year-by-year line chart (linear or log scale) of balance vs. cumulative contributions.