Caffeine Half-Life Calculator
Estimate caffeine half-life from your measurements.
Caffeine reference and label-based estimates last updated · reference source
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Dated static reference; no live data is fetched. Verify current source values and assumptions before relying on results.
What this tool does
Estimate caffeine half-life from your measurements. Typical assumed half-life 5 hours varies substantially. Beverage amounts are illustrative, not standardized servings; input the actual label mg and portion. Times after bedtime are treated as previous-day drinks.
How to use the Caffeine Half-Life Calculator
- Enter or select beverages, label caffeine amounts and consumption times.
- Enter or select target bedtime hh:mm.
- Enter or select assumed half-life (hours).
- Read the calculated result; change any measurement to compare alternatives.
Formula
each remaining mg=consumed mg×0.5^(elapsed hours/half-life); sum all drinks
- drinks
- Beverages, label caffeine amounts and consumption times
- bed
- Target bedtime HH:MM
- half
- Assumed half-life (hours)
Typical assumed half-life 5 hours varies substantially. Beverage amounts are illustrative, not standardized servings; input the actual label mg and portion. Times after bedtime are treated as previous-day drinks.
Worked example
For caffeine half-life calculator, the following measurements illustrate the exact method: Beverages, label caffeine amounts and consumption times: Filter coffee,150,09:00 Espresso,70,14:00; Target bedtime HH:MM: 23:00; Assumed half-life (hours): 5.
Inputs
- Beverages, label caffeine amounts and consumption timesFilter coffee,150,09:00 Espresso,70,14:00
- Target bedtime HH:MM23:00
- Assumed half-life (hours)5
Result
- Estimated caffeine at bedtime (mg)41.64
Results explained
- Estimated caffeine at bedtime (mg)
- Estimated caffeine at bedtime (mg) from the formula above. Typical assumed half-life 5 hours varies substantially. Beverage amounts are illustrative, not standardized servings; input the actual label mg and portion. Times after bedtime are treated as previous-day drinks.
Frequently asked questions
each remaining mg=consumed mg×0.5^(elapsed hours/half-life); sum all drinks
Typical assumed half-life 5 hours varies substantially. Beverage amounts are illustrative, not standardized servings; input the actual label mg and portion. Times after bedtime are treated as previous-day drinks.
No. These are general-information estimates, not diagnosis, treatment, fertility advice or exercise clearance. Consult a qualified health professional.
Individual physiology, measurement technique and health conditions may cause large differences from model estimates.
No. BAC estimates never establish that driving is safe or legal; do not drive after drinking.