Caffeine Half-Life Calculator
See when caffeine will clear your system enough for quality sleep.
Use Caffeine Half-Life Calculator ↓Caffeine Half-Life Calculator
Caffeine has a half-life of about 5-6 hours. See when it will clear your system enough for quality sleep.
Caffeine in Your System
Frequently Asked Questions
What is the half-life of caffeine?
Caffeine has an average half-life of about 5 hours in healthy adults, meaning half the caffeine from your coffee is still active 5 hours later. Individual variation ranges from 3-7 hours based on genetics and liver enzyme activity.
When should I stop drinking coffee for good sleep?
A general rule is to stop caffeine 8-10 hours before bedtime. If you sleep at 10 PM, your last coffee should be around noon to 2 PM. This allows enough time for caffeine to drop below sleep-disrupting levels.
Does decaf coffee contain caffeine?
Yes. Decaf typically contains 2-15 mg of caffeine per cup, compared to 80-100 mg in regular coffee. While much lower, sensitive individuals may still notice effects from multiple cups of decaf late in the day.