Caffeine remaining: model estimate
Estimates caffeine remaining now and at bedtime for a chosen elimination half-life.
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Calculation
Result
- Estimated amount at bedtime
- 65.0 mg
- Estimated amount remaining now
- 149.3 mg
- Entered doses in the last 24 hours
- 260 mg
- Chosen elimination half-life
- 5.0 h
- Comparison with the EFSA reference
- Not above the reference (≤ 400 mg)
Modelled caffeine mass, not a blood concentration or a diagnosis of sleep disruption.
Estimated amount remaining now
Time for the dose to halve in this model; initially 5 hours. Beverage contents are approximate — adjust the dose using the label.
Half-life varies between people and with pregnancy, illness and medicines. Enter an assumption; 5 hours is not your measured elimination rate. The remaining amount does not predict sleep quality. EFSA references of 400 mg/day for healthy adults and 200 mg/day during pregnancy do not guarantee individual safety.
The result updates as you change the fields. Your data never leaves the browser.
Only upon clicking, current data is sent to generate the PDF and is not stored.
How it is calculated
Remaining amount = dose × 2^(−t / T½). The daily total includes only entered doses from the last 24 hours.
Formula
Remaining amount = dose × 2^(−t / T½). The daily total includes only entered doses from the last 24 hours.
Limits of the method
Half-life varies between people and with pregnancy, illness and medicines. Enter an assumption; 5 hours is not your measured elimination rate. The remaining amount does not predict sleep quality. EFSA references of 400 mg/day for healthy adults and 200 mg/day during pregnancy do not guarantee individual safety.
Sources of the method
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the safety of caffeine. EFSA Journal, 2015;13(5):4102
- Guest NS et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr, 2021
- Drake C et al. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med, 2013
This calculation is for reference only and is not medical advice, a diagnosis or a prescription. If you have a medical condition, are pregnant, take medication or have any doubts, discuss the result with a physician or a qualified nutrition professional.
How to use the calculation
Enter the starting values
Use actual values and the appropriate units.
Adjust the parameters
Adjust the starting assumptions for your situation.
Read the result
Consider the model limitations; a calculation is not a measurement.
Frequently asked questions
What does the calculation show?
Estimates caffeine remaining now and at bedtime for a chosen elimination half-life.
What limitations apply?
Half-life varies between people and with pregnancy, illness and medicines. Enter an assumption; 5 hours is not your measured elimination rate. The remaining amount does not predict sleep quality. EFSA references of 400 mg/day for healthy adults and 200 mg/day during pregnancy do not guarantee individual safety.
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What next
Formula breakdowns, biomarker reference ranges and nutrition articles with cited sources are in the NutriFit knowledge base.
Go to the knowledge base