Caffeine Half-life Calculator

May 5, 2022 - Reading time: ~1 minute

The half-life of caffeine can be used to calculate how long coffee will affect you after you drink some. Knowing this can help you adjust your coffee intake in order to improve your sleep schedule, or help you determine how often you should drink caffeine in order to maintain a stable level of caffeine through the day.

The biological half-life of caffeine in typical adults is between 5 to 6 hours. This means if you had 100 grams of caffeine, you would have around 50 grams after 5 hours.

Keep in mind that after the amount becomes very small, it is likely that the body will dispose of it all at once rather than halving the amount forever.


It is very easy to calculate this with a calculator. To calculate the caffeine you will have 5 hours later, multiply the amount you have with 0.5, and to calculate the amount you will have 1 hour later, multiply the amount by 0.09.

Caffeine Half-Life Calculator

This is a tool to calculate approximately how much caffeine you'll have in your blood based on your intake. Please note that this is just informative and should not be used for medical or health purposes. The format of each line is the time you had Caffeine and the amount in milligrams.


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Parnika shukla
Written by Parnika shukla on May 4, 2023

Reaally nice. Adding days(like day 1, day 2) and number or hours to the page will also help give better information.