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Caffeine Calculator

Track your daily caffeine intake and stay within healthy limits. See how much caffeine is in your favorite beverages and understand its effects on your body.

Select Your Daily Limit

Today's Caffeine

400mg remaining

0 / 400mg

You're well within your daily limit.

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Caffeine Effects Timeline

15-45 min
Peak Alertness

Caffeine reaches peak levels in your bloodstream. You feel most alert and focused.

3-5 hours
Half-Life

Half of the caffeine is still in your system. Effects start to diminish.

6-8 hours
Sleep Cutoff

Avoid caffeine within 6-8 hours of bedtime for quality sleep.

10-12 hours
Full Elimination

Most caffeine has been metabolized. Ready for your next morning cup!


Understanding Caffeine

Benefits (in moderation)

  • Increased alertness and focus
  • Improved physical performance
  • Enhanced mood and cognitive function
  • May reduce risk of certain diseases

Side Effects (excess)

  • Anxiety and restlessness
  • Sleep disruption and insomnia
  • Increased heart rate
  • Digestive issues

Daily Limits

  • Adults: Up to 400mg/day (FDA)
  • Pregnant: 200mg or less
  • Teens: 100mg or less
  • Children: Avoid caffeine

Sleep Tips

  • Stop caffeine 6-8 hours before bed
  • Avoid afternoon coffee if sensitive
  • Consider switching to decaf after noon
  • Watch hidden sources (chocolate, some meds)

Frequently Asked Questions

How much caffeine is too much?

The FDA considers 400mg per day safe for most healthy adults - about 4 cups of coffee. However, sensitivity varies greatly. If you experience jitters, anxiety, or sleep issues, you may want to reduce your intake. Pregnant women should limit to 200mg.

Does decaf coffee have caffeine?

Yes! "Decaf" isn't caffeine-free. A typical cup of decaf coffee contains about 2-15mg of caffeine (compared to 95mg in regular). This adds up if you drink multiple cups, so very caffeine-sensitive people should be aware.

Why does caffeine affect people differently?

Genetics play a major role! Some people metabolize caffeine quickly (fast metabolizers) while others process it slowly. Age, liver function, medications, and regular caffeine consumption also affect how your body handles caffeine.

Can you become addicted to caffeine?

Caffeine is physically addictive, but it's considered mild compared to other substances. Regular users can experience withdrawal symptoms (headaches, fatigue, irritability) when stopping suddenly. Tapering off gradually over a week or two helps minimize these effects.