Half-Life Calculator
Calculate the remaining quantity, elapsed time, or half-life of a substance undergoing exponential decay.
Calculation Parameters
Adjust the values below.
Calculated Result
Expert Tip
Ensure units are correctly formatted (e.g. Kelvin for gas temperatures and liters for volumes) to get chemically accurate outputs.
How this Calculator Works
This calculator allows you to solve Half-Life problems dynamically. Adjust the input parameters using the sliders or selection menu below:
- Initial Amount (N0) (Range: 1 to 1000, Default: 100)
- Half-Life duration (t1/2) (Range: 1 to 1000, Default: 100)
- Time Elapsed (t) (Range: 1 to 1000, Default: 50)
The results are computed instantly and updated in the results panel on the right.
Formula & Methodology
Where:
- Initial Amount: Parameter value.
- Half-Life duration: Parameter value.
- Time Elapsed: Parameter value.
Step-by-Step Calculation Example
To calculate Half-Life manually, follow these steps:
- Identify the input parameters. For example:
- Initial Amount (N0) = 100
- Half-Life duration (t1/2) = 100
- Time Elapsed (t) = 50
- Apply the formula:
N(t) = N0 * (0.5)^(t / t_1/2)
- Verify the calculated value which is updated instantly in the results panel on the right.
Frequently Asked Questions
What is half-life (t1/2)? ▼
Half-life is the time required for half of the radioactive nuclei in a sample to undergo decay.
What is the first-order half-life formula? ▼
t1/2 = ln(2) / λ ≈ 0.693 / λ, where λ is the decay constant.
Is half-life dependent on initial sample quantity? ▼
No, first-order radioactive decay half-life is constant and completely independent of initial sample size.