Caffeine Calculator
See how much caffeine is left in your system after a number of hours.
Caffeine remaining
—
Of daily limit—
Half-life is about 5 to 6 hours; 400 mg/day is a common adult limit. This is an estimate for general guidance, not medical advice. For a plan that fits you, talk to a doctor or qualified professional.
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How it works
Remaining = intake × 0.5^(hours ÷ 5.7)Frequently Asked Questions
How does the Caffeine Calculator work?
See how much caffeine is left in your system after a number of hours.
Is this medical advice?
No. It gives general estimates only. For decisions about your health, speak with a qualified professional.