Formulas used
- Remaining fraction = 0.5^(interval / half-life).
- Accumulation factor = 1 / (1 - remaining fraction).
- Peak after N intervals = amount x (1 - remaining^N) / (1 - remaining).
- Trough = peak x remaining fraction.
Tools
Accumulation Calculator
Model simple first-order half-life accumulation from your own half-life, interval, and amount inputs.
Remaining before next interval
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Steady-state accumulation factor
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Estimated peak after intervals
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Estimated trough
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Steady-state peak
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Steady-state trough
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Time to steady state estimate
~90%
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~95%
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~97%
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Interval curve
Calculator notes
Half-life accumulation model
This tool estimates how much of a repeated amount remains across fixed intervals when clearance follows a simple first-order half-life.
It treats each interval as the same size and timing. Amount units are carried through as labels, so mg, mcg, or units should not be mixed within one run.
Assumptions
The model assumes first-order elimination, fixed spacing, and no separate absorption or distribution phase. Steady-state estimates use about 3.32, 4.32, and 5.06 half-lives for 90%, 95%, and 97%.
Common inputs
Enter half-life and interval in hours or days. Use the same meaning for each amount entry, whether the label is mg, mcg, or units.
Related terms and tools
Related definitions include pharmacokinetics and pharmacodynamics. For preparation and unit math, see the reconstitution calculator and unit converter.