Ever wonder when that afternoon coffee will wear off? Find out how long caffeine will stay in your system.
Enter the number of cups to see the results.
That jolt of energy you feel after your morning cup of coffee is thanks to caffeine, a powerful stimulant that affects your central nervous system. But have you ever wondered how long those effects truly last? The answer lies in a concept called "half-life."
The half-life of a substance is the time it takes for your body to metabolize and reduce the concentration of that substance by half. For caffeine, the average half-life is around 5 hours. This means if you consume 100mg of caffeine, about 50mg will still be in your system 5 hours later. Another 5 hours, and you'll have roughly 25mg remaining, and so on.
This calculator uses the half-life principle to provide an estimate of how long caffeine from your coffee intake will be actively circulating in your system. Understanding this can help you better time your coffee breaks to avoid disrupting your sleep patterns and ensure you get the most out of your rest.