basic

Integrated Rate Law — First-Order Concentration Calculator

[A] = [A]₀ · exp(−k · t) for a first-order decay.

Compute the concentration of reactant A at time t for a first-order reaction: [A] = [A]₀ · e^(−k·t). Also reports half-life t½ = ln 2 / k.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

mol/L
1/s
s

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

[A] = [A]₀ · exp(−k · t); t½ = ln 2 / k.

In depth

Compute the concentration of reactant A at time t for a first-order reaction: [A] = [A]₀ · e^(−k·t). Also reports half-life t½ = ln 2 / k.