Caffeine Calculator
Track your daily caffeine intake and see when it clears your system. Add coffee, tea, energy drinks, and more to monitor your consumption.
Caffeine Calculator
Low caffeine intake. You have plenty of room within safe limits.
Sleep Impact
Time when caffeine drops below 25mg (safe for sleep)
Time for your body to eliminate half the caffeine
Caffeine Content Guide
Caffeine Facts
Safe Limits
- • Adults: Up to 400mg/day (FDA)
- • Pregnant: Limit to 200mg/day
- • Teens: 100mg/day maximum
- • Children: Avoid caffeine
Common Effects
- • Increased alertness
- • Improved concentration
- • Enhanced athletic performance
- • May cause jitters, anxiety at high doses
How to Use the Caffeine Calculator
Add Your Caffeinated Drinks
Select from over 15 drink types including drip coffee, espresso, cold brew, tea, energy drinks, and more. Choose the drink you consumed and click Add to include it in your daily tracking.
Enter Quantity and Time Consumed
Specify how many servings you had and when you consumed each drink. The time is important for calculating when caffeine will leave your system and affect your sleep.
Monitor Your Daily Intake
View your total caffeine consumption against the FDA-recommended 400mg daily limit. The progress bar shows how close you are to the safe maximum, with warnings if you exceed it.
Check Sleep Impact and Clearance Time
See when caffeine levels will drop below 50mg (sleep-safe level) based on the 5-hour half-life. Plan your last caffeinated drink accordingly to avoid sleep disruption.
Pro tip: Your data is processed entirely in your browser. Nothing is sent to any server, ensuring complete privacy.
Understanding Caffeine
Caffeine is the world's most widely consumed psychoactive substance. Found naturally in coffee beans, tea leaves, and cacao, it works by blocking adenosine receptors in the brain, reducing drowsiness and increasing alertness.
While moderate caffeine consumption is generally safe and may even have health benefits, too much can cause negative effects like anxiety, insomnia, and increased heart rate. Understanding your intake helps you enjoy caffeine's benefits while avoiding its downsides.
Caffeine Content by Source
- Drip Coffee: 95mg per 8oz cup (most common source)
- Espresso: 63mg per 1oz shot (highest concentration)
- Cold Brew: 200mg per 16oz (longest brewing extracts more caffeine)
- Black Tea: 47mg per 8oz cup (gentler effect due to L-theanine)
- Energy Drinks: 80-160mg per can (varies widely by brand)
Frequently Asked Questions
How much caffeine is safe per day?
The FDA recommends up to 400mg of caffeine per day for healthy adults - roughly 4 cups of brewed coffee. Pregnant women should limit intake to 200mg, and teenagers should stay under 100mg. Children should avoid caffeine altogether.
How long does caffeine stay in your system?
Caffeine has a half-life of about 5 hours, meaning half of it is eliminated in that time. It typically takes 10-12 hours for caffeine to fully clear your system. Factors like age, liver function, and medications can affect this.
How late can I drink coffee and still sleep well?
Most sleep experts recommend avoiding caffeine at least 6 hours before bedtime. If you go to bed at 10 PM, your last caffeinated drink should be around 4 PM. Our calculator shows when caffeine will drop to sleep-safe levels.
Which drink has the most caffeine?
Cold brew coffee typically has the most caffeine (200mg per 16oz), followed by pre-workout supplements (200mg), drip coffee (95mg per 8oz), and energy drinks (80-160mg). Espresso has high concentration but small serving size (63mg per shot).
What are the symptoms of too much caffeine?
Consuming too much caffeine can cause: jitters, anxiety, rapid heartbeat, insomnia, headaches, digestive issues, and increased blood pressure. Severe overdose (rare) can cause seizures. If you experience these symptoms, reduce your intake.
Does caffeine in tea affect you differently than coffee?
Tea contains L-theanine, an amino acid that may moderate caffeine's effects, providing a calmer alertness compared to coffee. Tea also has less caffeine per cup (28-47mg vs 95mg), resulting in a gentler energy boost.
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