What the curve assumes
The model treats each entered amount as appearing instantly in one compartment, then declining with a constant first-order elimination rate derived from the half-life.
Pharmacokinetic Math Tool
Half-Life & Accumulation Visualizer
Explore how a user-entered amount changes over time under a simple first-order elimination model. Switch between one input and repeated inputs to see theoretical decay, accumulation, and peak/trough behavior.
This is an educational model—not a dose calculator, treatment planner, or recommended scheduling tool. Learn the underlying terms in the half-life, pharmacokinetics, and pharmacodynamics glossary entries.
Starting amountUnits are labels only here; this tool does not convert between mg, mcg, or IU.
Half-life
Visualize for
Theoretical amount over time
First-order elimination curve
Each input is treated as instantaneous, then declines exponentially according to the half-life you entered.
One-compartment teaching model
Amount at window end
0.016 relative units
Half-life count in window
6
After 5 half-lives
0.031 relative units
Elimination constant
0.6931 / hour
Model limitations
Real pharmacokinetics can differ because absorption may not be instantaneous, distribution may involve multiple compartments, clearance can be nonlinear, bioavailability can vary, and active metabolites can matter. A reported half-life can also differ by study, formulation, route, and population. This visualizer is educational math only and should not be used to choose a dose or dosing interval.
How the model works
Open this section for the assumptions, repeated-input math, and plain-language half-life explanation.
How the model works
Open this section for the assumptions, repeated-input math, and plain-language half-life explanation.
What repeated inputs show
When the same amount is added at a fixed user-entered interval, leftover material from earlier inputs can overlap with later inputs. The graph sums those remaining amounts mathematically.
What it does not tell you
It does not determine an appropriate dose, interval, target level, route, formulation, or treatment plan. Those require compound- and person-specific clinical context that this generic model does not have.
Half-life math in plain language
In a first-order model, one half-life leaves 50% of the modeled amount, two half-lives leave 25%, three leave 12.5%, four leave 6.25%, and five leave 3.125%.
The exponential form is equivalent to multiplying by 0.5 raised to elapsed time divided by half-life.
For repeated equal inputs, the accumulation ratio in this idealized model depends only on the relationship between the interval and half-life. Shorter intervals relative to the entered half-life create more mathematical overlap.
Real concentration-time profiles may not follow this shape because absorption, distribution, clearance, bioavailability, active metabolites, and nonlinear behavior can all matter.