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Caffeine Calculator
Estimate your daily caffeine intake from coffee, tea, soda, and energy drinks. Ensure you stay within safe limits.
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Understanding Caffeine Intake
Caffeine is a natural stimulant most commonly found in tea, coffee, and cacao plants. It works by stimulating the brain and central nervous system, helping you stay alert and preventing the onset of tiredness.
Common Caffeine Sources
- Brewed Coffee (8 oz): ~95 mg
- Espresso (1 oz): ~63 mg
- Black Tea (8 oz): ~47 mg
- Green Tea (8 oz): ~28 mg
- Cola (12 oz): ~30-40 mg
- Energy Drinks (8 oz): ~80 mg (can vary widely)
⚠️ Warning Signs of Overdose
If you experience jitters, rapid heartbeat, anxiety, or dizziness, you may have consumed too much caffeine. Stop intake immediately and drink water to help flush your system.
💡 Expert Tip from Sarah Jenkins, RD
Avoid caffeine at least 6 hours before bedtime to prevent sleep disruption. If you're sensitive to caffeine, consider switching to decaf or herbal tea after noon.
Frequently Asked Questions
How much caffeine is safe per day?
For most healthy adults, up to 400 milligrams (mg) of caffeine a day appears to be safe. That's roughly the amount of caffeine in four cups of brewed coffee, 10 cans of cola or two energy shot drinks.
What are the side effects of too much caffeine?
Consuming too much caffeine can cause insomnia, nervousness, restlessness, irritability, upset stomach, fast heartbeat, and muscle tremors.
How long does caffeine stay in your system?
The half-life of caffeine is about 5 hours. This means if you consume 200 mg of caffeine, 100 mg will still be in your system 5 hours later.