Caffeine Clearance Simulator
Simulate remaining caffeine from several doses using a chosen half-life, with current totals and future decay scenarios.
Caffeine timing model workspace
Chosen half-life; no blood-level or bedtime claim
Your caffeine timing scenario
104.16 mg · modelled caffeine remaining
Chosen half-life 5 hours · immediate absorption assumption
Full result table
| Future hours | Modelled remaining mg | Share of current % |
|---|---|---|
| 0 | 104.156191 | 100 |
| 0.5 | 97.181162 | 93.303299 |
| 1 | 90.673231 | 87.055056 |
| 1.5 | 84.601116 | 81.22524 |
| 2 | 78.935632 | 75.785828 |
| 2.5 | 73.649549 | 70.710678 |
| 3 | 68.717459 | 65.975396 |
| 3.5 | 64.115656 | 61.557221 |
| 4 | 59.822023 | 57.434918 |
| 4.5 | 55.815921 | 53.588673 |
| 5 | 52.078095 | 50 |
| 5.5 | 48.590581 | 46.65165 |
| 6 | 45.336615 | 43.527528 |
| 6.5 | 42.300558 | 40.61262 |
| 7 | 39.467816 | 37.892914 |
| 7.5 | 36.824774 | 35.355339 |
| 8 | 34.358729 | 32.987698 |
| 8.5 | 32.057828 | 30.77861 |
| 9 | 29.911011 | 28.717459 |
| 9.5 | 27.90796 | 26.794337 |
| 10 | 26.039048 | 25 |
| 10.5 | 24.295291 | 23.325825 |
| 11 | 22.668308 | 21.763764 |
| 11.5 | 21.150279 | 20.30631 |
| 12 | 19.733908 | 18.946457 |
A simplified one-compartment elimination model, not a blood concentration measurement or a safe bedtime test. Real half-life varies with physiology, medicines and other factors. It does not recommend caffeine doses, infer sleep effects or decide whether a medicine interaction is safe.
Let’s work it out.
Ask about this tool, enter your values, or understand your result.
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How to use Caffeine Clearance Simulator
- Add milligrams of caffeine for each drink or product and pair each with the hours elapsed since consumption.
- The half-life controls how quickly each dose declines.
- The curve extends the same assumption over the selected future horizon.
Worked example
With a five-hour half-life, a 100 mg dose taken five hours ago leaves a modelled 50 mg. Two identical such doses sum to 100 mg.
Formula, accuracy & limitations
Remaining mg for one dose = dose × 2^(−elapsed hours/half-life). Sum doses for the current total; add future hours to each elapsed time for the decay curve. Absorption is assumed immediate.
A simplified one-compartment elimination model, not a blood concentration measurement or a safe bedtime test. Real half-life varies with physiology, medicines and other factors. It does not recommend caffeine doses, infer sleep effects or decide whether a medicine interaction is safe.
These outputs use the stated model and your supplied inputs. A mathematically consistent model can still differ from personal measurements. Scenario curves and formula comparisons are not statistical confidence intervals.
Source and method context ↗Enter actual doses and elapsed times
Add milligrams of caffeine for each drink or product and pair each with the hours elapsed since consumption. Clock time is intentionally not used, avoiding ambiguity across midnight or time zones. A product volume in millilitres is not a caffeine dose without a concentration or label.
Choose a half-life assumption explicitly
The half-life controls how quickly each dose declines. All entries share the chosen value, and absorption is simplified as immediate. The output is a modelled remaining mass, not a laboratory blood level or a personalised prediction of how alert, anxious or sleepy you will feel.
Read future decay without a zero-caffeine promise
The curve extends the same assumption over the selected future horizon. Exponential decay approaches zero rather than reaching an exact clearance deadline. Personal factors can make actual elimination faster or slower, so the model provides no universal safe bedtime or medication advice.
Distinguish elapsed time from a future clock deadline
A five-hour half-life gives 50 mg remaining from 100 mg after five hours, 25 mg after ten hours and 12.5 mg after fifteen hours under the model. Adding another 100 mg dose starts another declining contribution, which is summed rather than resetting the original curve. These calculations omit absorption time and individual kinetics. Because elapsed hours are used, the page needs no timezone, but it also cannot infer a bedtime, medication schedule or threshold below which caffeine has no effect.
Frequently asked questions
Is this different from the intake calculator?
The intake calculator adds consumed caffeine. This model accounts for elapsed time and an elimination assumption for each supplied dose.
Can I use the output as a blood concentration?
The result is modelled milligrams remaining under a simple assumption. No distribution volume or measured plasma concentration is provided.
Why does the curve never reach exactly zero?
Exponential decay halves the remaining amount repeatedly. A numerical display may round a tiny value, but that is not a measured clearance time.
Does less remaining caffeine mean sleep is unaffected?
The model does not predict sleep response. Individual sensitivity and timing effects are not captured by remaining mass alone.
