Caffeine Half-Life Calculator
Calculate how much caffeine remains in your system at bedtime and when to stop drinking coffee.
Inputs
mg
Results
Caffeine at Bedtime
57 mg
Sleep Disruption RiskYes — Above threshold
Latest Safe Coffee Time11:23
Your Caffeine Half-Life5 hrs
Hours to Safe Level11.6 hrs
Hours Until Bedtime9 hrs
How to Use This Calculator
- Enter the total milligrams of caffeine consumed today.
- Set your consumption time using the hour and minute fields.
- Input your target bedtime hour.
- Review Caffeine at Bedtime in mg to see how much will still be in your system when you sleep.
- Adjust your last caffeine cutoff time until the bedtime level drops below 50 mg for minimal sleep disruption.
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