Estimate how much of a dose remains after a given time, assuming simple exponential decay.
| Remaining | – |
| Half-lives | – |
Use this calculator for a one-compartment sketch: remaining = starting amount × 2^(−elapsed / half-life). The starting amount can be any unit; remaining is returned in the same unit. Half-lives elapsed = elapsed ÷ half-life.
This is not a multi-compartment pharmacokinetic model and not a dosing schedule. Food caffeine already uses a 5 h sketch elsewhere; this page is generic.
Starting amount: Quantity at time zero, in any unit.
Half-life (h): Time for the amount to fall by half, in hours.
Elapsed (h): Hours since that dose.
Remaining: Amount left after exponential decay.
Half-lives: How many half-lives have passed.
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