Caffeine Sleep Cutoff
Latest time to drink coffee for a given bedtime.
Time elapsed by bedtime: 9.0 hours
Cutoff (last coffee at 50 mg threshold): 4.6 hours before bed
Latest coffee for 23:00 bedtime: 06:22 PM
Caffeine reference
- Espresso shot: ~63 mg · Drip coffee 8 oz: ~95 mg
- Energy drink (Red Bull 8.4 oz): ~80 mg
- Black tea 8 oz: ~47 mg · Green tea: ~28 mg
- Coke 12 oz: ~34 mg · Diet Coke: ~46 mg
- Pre-workout: 100–300 mg
Half-life of caffeine in healthy adults averages 5 hours but varies from 2 to 12. Pregnancy doubles it. Smoking shortens it. The 50 mg threshold is the rough disruption point in the Drake et al. 2013 sleep study.
About
Enter your dose, coffee time, and bedtime. Using a 5-hour caffeine half-life, the tool projects how much caffeine remains at bedtime and the latest dose time that keeps you below the sleep-disruption threshold.
How to use
- Enter dose and times.
- Set your threshold.
FAQ
Why 50 mg threshold?+
Drake et al. 2013 found significant sleep disruption from 400 mg taken at bedtime, less from 200 mg taken 6 hours before. 50 mg is a conservative bedtime estimate that works for most adults.