Science Calculators

Half-Life Calculator

Use this free half-life calculator to calculate accurate results instantly with clear inputs, formulas, and rounded answers.

Last updated July 23, 2026
Half-Life

Half-Life Calculator

Quantity remaining
Percent remaining
Half-lives elapsed
Results are estimates for informational purposes. Verify critical calculations and project requirements independently.

How to Use the Half-Life Calculator

Enter the requested values, review the units, and select Calculate Half-Life. The result updates immediately using the formula below.

Formula

Remaining quantity = initial quantity × (½)^(elapsed time ÷ half-life).

Example and Accuracy

The default values provide a working example. Change any input to calculate your own result. The calculator keeps full internal precision and rounds displayed values for readability.

Important Note

This calculator provides an informational estimate. Verify critical financial, medical, construction, scientific, or legal decisions with an appropriate qualified professional.

Calculation Standards

This tool uses documented formulas and high-precision internal values. Displayed results may be rounded for readability. Review the assumptions and verify important decisions with a qualified professional.

Read our calculation methodology