Caffeine Intake Calculator
Calculate your daily caffeine intake and compare it to recommended limits. Check remaining caffeine based on half-life.
ℹ️ What is Caffeine?
Caffeine is a natural stimulant found in coffee, tea, and energy drinks. In moderate amounts, it enhances alertness and concentration. However, excessive intake may cause anxiety, insomnia, and headaches.
📖 How to Use
- Select the drinks you've consumed today and their quantities
- Enable time tracking if you want to calculate remaining caffeine
- Click Calculate
- Check your total caffeine intake and percentage of daily limit
✨ Features
- ✓8 drink presets (coffee, tea, energy drinks, etc.)
- ✓Percentage of recommended daily intake display
- ✓Half-life based remaining caffeine calculation
- ✓Sleep-safe time estimation
📐 Formula
Remaining = Intake × 0.5^(elapsed time ÷ half-life)💡 How It Works
- •Caffeine has an average half-life of 5-6 hours. If you consume 100mg, about 50mg remains after 5.5 hours.
- •The recommended daily caffeine intake for adults is 400mg, equivalent to about 2-3 cups of americano.
- •Caffeine reaches peak blood concentration 30-60 minutes after consumption and takes about 10 hours to be fully eliminated.
- •When caffeine drops below 100mg in your body, it typically doesn't significantly affect sleep.
❓ FAQ
Q. How much caffeine is in one cup of americano?
A. A typical americano (12oz/355ml) contains about 150mg of caffeine. This can vary based on the number of espresso shots.
Q. How many cups of coffee can I drink per day?
A. For healthy adults, up to 400mg per day is recommended. That's about 2-3 americanos or 6 espresso shots.
Q. What is caffeine half-life?
A. Half-life is the time it takes for half of a substance to be eliminated from your body. For caffeine, it's about 5-6 hours on average, though it varies by individual.
Q. When should I stop drinking coffee to not affect sleep?
A. Generally, avoid caffeine after 2 PM (8 hours before bedtime). If you're sensitive to caffeine, stop even earlier.
Q. Which has more caffeine - green tea or coffee?
A. Coffee has much more caffeine. One cup of green tea (30mg) has about 5 times less caffeine than one americano (150mg).