Caffeine Calculator
Estimate how much caffeine is still in your system hours after a coffee or energy drink, using caffeine’s roughly five-hour half-life.
Result
Caffeine still in your body
87mg
- Share remaining
- 43.53%
- Hours from the drink until under 50 mg
- 10hours
Common questions
How much caffeine is safe in a day?
The FDA says up to 400 mg a day is generally safe for healthy adults, about four cups of brewed coffee.