First Order Half Life Calculator
Calculate half-life from a first-order rate constant.
First Order Half Life measurements
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Result
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CategoryChemistry
Inputs1
CalculationIn browser
How to calculate first order half life
This calculator finds half-life of a first-order reaction from its rate constant.
How the calculation works
Half-life = ln(2) ÷ k.
Example
k=0.02/min: ln(2)÷0.02 ≈ 34.66 min.
Frequently asked questions
How is Result calculated?
Result = log(2) ÷ [Rate constant].
Is the First Order Half Life Calculator free to use?
Yes — every calculator on Simple Calculator Tools is free, runs in your browser, and does not require an account.
Quick Insight
First Order Half Life Calculator
Half-life = ln(2) ÷ k.
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Your personalized explanation
Calculate a result above and this guide will help you interpret it using this calculator's own formula and explanation.
Pro Tips for First Order Half Life
- First-order half-life is constant regardless of starting concentration.
- Match units to what you want half-life expressed in.
Common First Order Half Life Mistakes to Avoid
- Applying this formula to a non-first-order reaction, where half-life would depend on concentration.
When to Use This Calculator
This calculator finds half-life of a first-order reaction from its rate constant.
Content reviewed: August 2026 · Robert Threadgill