Caffeine Calculator
Track daily caffeine intake
Formula
Coffee: ~95mg per cup
Tea: ~47mg per cup
Energy drink: ~80mg
Safe limit: 400mg/day
Caffeine Content
| Coffee (8oz) | 80-100mg |
| Espresso | 63mg |
| Black Tea | 40-70mg |
| Green Tea | 25-45mg |
| Cola | 30-40mg |
Related
Complete Guide to Caffeine Calculator
Caffeine is the world's most widely consumed psychoactive substance. It can boost alertness, improve performance, and enhance mood - but too much can cause anxiety, insomnia, and dependence.
Safe Caffeine Limits
For healthy adults, up to 400mg daily (about 4 cups of coffee) is generally safe. Pregnant women should limit to 200mg. Children and teens should consume significantly less based on body weight.
Caffeine Half-Life
Caffeine has a half-life of 5-6 hours, meaning half the caffeine from your afternoon coffee is still in your system at bedtime. For better sleep, avoid caffeine after 2pm (or earlier if you're sensitive).
Signs of Too Much Caffeine
- Anxiety, jitters, or restlessness
- Rapid heartbeat
- Difficulty sleeping
- Digestive issues
- Headaches (or headaches when skipping caffeine)
Frequently Asked Questions
Up to 400mg daily for healthy adults - about 4 cups of coffee. Pregnant women should limit to 200mg. People with anxiety or heart conditions may need less. Listen to your body.
Caffeine has a half-life of 5-6 hours. If you drink 200mg at 3pm, you still have 100mg in your system at 9pm. This is why afternoon caffeine disrupts sleep even if you fall asleep.
For most people, stop caffeine by 2pm for good sleep. If you're sensitive, stop by noon. Some fast metabolizers can drink coffee later without issues - know your own response.
Yes. Regular caffeine use leads to tolerance and mild physical dependence. Withdrawal symptoms (headache, fatigue, irritability) typically last 2-9 days if you quit. Tapering is easier than cold turkey.
Mildly, but coffee and tea still contribute to hydration. The fluid in caffeinated drinks more than offsets the small diuretic effect. You don't need extra water to compensate.
For most people, moderate caffeine (up to 400mg) doesn't increase heart disease risk. Some studies suggest it may be protective. Those with arrhythmias should consult their doctor.
Yes! Caffeine improves endurance, strength, and focus. 3-6mg per kg bodyweight taken 30-60 minutes before exercise is effective. It's one of the few legal performance enhancers.