CAFFEINE
HALF-LIFE
CALCULATOR
Caffeine has a half-life of 3-7 hours depending on your metabolism. Calculate how long caffeine stays in your system and discover your optimal cutoff time for better sleep quality.
// ENTER CAFFEINE DATA
Enter the amount of caffeine consumed in milligrams.
Genetics, smoking, and medications affect caffeine metabolism.
// COMMON CAFFEINE SOURCES
Click to auto-fill caffeine amount:
// CAFFEINE ANALYSIS
CAFFEINE AT BEDTIME
(50% of original)
Caffeine levels should be low enough for quality sleep.
TIME TO 25%
10:00
Good for sleep
HALF-LIFE
5h
Based on metabolism
RECOMMENDED CUTOFF TIME
Last caffeine intake for your target bedtime
CAFFEINE TIMELINE
// CAFFEINE_SCIENCE
UNDERSTANDING CAFFEINE METABOLISM
Caffeine half-life refers to the time it takes for your body to eliminate half of the caffeine you consumed. For most adults, this is around 5 hours, but it can range from 3-7 hours based on individual factors.
FACTORS AFFECTING CAFFEINE METABOLISM
- Genetics: CYP1A2 gene variants determine if you're a fast or slow metabolizer
- Smoking: Smokers metabolize caffeine up to 50% faster
- Pregnancy: Caffeine half-life can double during pregnancy
- Medications: Birth control and certain drugs slow caffeine metabolism
- Liver health: Liver conditions significantly affect metabolism speed
- Age: Older adults may metabolize caffeine more slowly
CAFFEINE AND SLEEP
Caffeine blocks adenosine receptors in your brain, preventing the buildup of sleep pressure. Even if you can fall asleep after caffeine, studies show it can reduce deep sleep and overall sleep quality. For optimal sleep, aim to have less than 25% of your caffeine remaining at bedtime.
CAFFEINE CONTENT REFERENCE
| BEVERAGE | SERVING SIZE | CAFFEINE (mg) |
|---|---|---|
| Espresso | 1 shot (1oz) | 63 mg |
| Drip Coffee | 8 oz | 95 mg |
| Cold Brew Coffee | 8 oz | 200 mg |
| Black Tea | 8 oz | 47 mg |
| Green Tea | 8 oz | 28 mg |
| Energy Drink | 8 oz | 80-150 mg |
| Cola | 12 oz | 35-45 mg |
| Dark Chocolate | 1 oz | 12 mg |
TIPS FOR CAFFEINE MANAGEMENT
- Morning window: Consume caffeine within the first 8-10 hours after waking
- Cutoff time: Set a personal cutoff time based on your metabolism and bedtime
- Track sensitivity: Monitor how caffeine affects your sleep quality
- Consider alternatives: Switch to decaf or herbal tea in the afternoon
- Stay hydrated: Caffeine is a mild diuretic, so drink extra water
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Disclaimer: This calculator provides general estimates based on average caffeine metabolism. Individual responses to caffeine vary significantly based on genetics, medications, and health conditions. This tool is for educational purposes only and is not a substitute for professional medical advice.