Caffeine Half-Life Calculator
Calculate how long caffeine stays in your system and its effect on sleep based on consumption time.
Caffeine Half-Life
Caffeine has an average half-life of about 5 hours in healthy adults, meaning half the caffeine is eliminated every 5 hours. Factors like genetics, age, medications, and liver function can affect this (range: 3-7 hours). Sleep experts recommend keeping caffeine below 50 mg at bedtime, which typically means no coffee after early afternoon.
About This Tool
The Caffeine Half-Life Calculator helps users understand how long caffeine remains active in their system and its impact on sleep quality. Ideal for coffee lovers concerned about evening consumption.
Enter your last cup's time, the amount of caffeine consumed, and personal factors like age and weight to see when half-life is reached and potential effects on sleep duration and quality.
Use this tool to plan caffeine intake around bedtime or work shifts. All calculations are performed locally in your browser; no data is sent anywhere.