How to Calculate Half-Life
What is Half-Life?
A half-life calculator computes radioactive decay, drug elimination, or any exponential decay process. The half-life is the time for a quantity to reduce to half its starting value.
Formula
- N
- N₀ / 2ⁿ — N₀ / 2ⁿ
Step-by-Step Guide
- 1N(t) = N₀ × (½)^(t/t½)
- 2After n half-lives: N = N₀ / 2ⁿ
- 3Decay constant λ = ln(2) / t½ ≈ 0.693 / t½
- 4Mean lifetime τ = 1/λ = t½ / ln(2)
Worked Examples
Frequently Asked Questions
What is Half-Life?
A half-life calculator computes radioactive decay, drug elimination, or any exponential decay process. The half-life is the time for a quantity to reduce to half its starting value
How accurate is the Half-Life calculator?
The calculator uses the standard published formula for half-life. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.
What units does the Half-Life calculator use?
This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.
What formula does the Half-Life calculator use?
The core formula is: N(t) = N₀ × (½)^(t/t½). Each step in the calculation is shown so you can verify the result manually.
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