Half-Life Decay Calculator
Explore how a hypothetical amount falls over time in a first-order elimination model.
Explore half-life decay
Result
A simplified first-order model using the half-life you supply. This does not account for absorption, active metabolites or individual variation, and does not select a dosing interval.
How to interpret research measurementsEnter a half-life and an elapsed time in hours. The tool calculates the percentage remaining and shows a reference table for successive half-lives. It uses the value you supply and does not provide compound-specific half-life estimates or dosing schedules.
How to Use
Enter a positive half-life in hours from the source you are evaluating.
Enter elapsed time in hours, including zero for the starting point.
Read the remaining percentage and reference table.
Formula
Remaining percentage = 100 × 0.5^(elapsed time / half-life)Example
For an illustrative 4-hour half-life, 50% remains after 4 hours and 25% after 8 hours. This is a mathematical example, not a peptide half-life claim.
Frequently Asked Questions
Does this predict blood concentration?
No. It models a percentage under a simplified first-order assumption. Absorption, distribution, active metabolites and individual variation are not included.
Can I use it to choose a dosing interval?
No. The model does not determine a therapeutic level, clinical effect or safe dosing interval.