☕Coffee Calculator
Calculate your total caffeine intake from coffee and other caffeinated drinks, and compare it to your personalised safe daily limit. Based on your body weight and caffeine sensitivity, the calculator tells you how many cups are safe and what percentage of your daily limit you've reached.
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Total Caffeine
190 mg
Caffeine: Consumed vs. Remaining Daily Budget
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Coffee Calculator: Safe Daily Caffeine Intake by Body Weight
The FDA recommends a maximum of 400 mg of caffeine per day for healthy adults — roughly 4 cups of drip coffee. Personalised by body weight, the safe threshold is approximately 5.7 mg per kilogram. A 70 kg person: 70 × 5.7 = 399 mg. One espresso = 63 mg; one drip coffee = 95 mg; one energy drink = 80 mg.
Formula: Daily limit = body weight (kg) × 5.7 mg/kg × sensitivity factor
| Drink | Caffeine (mg) | Cups to 400 mg limit |
|---|---|---|
| Espresso (1 shot) | 63 mg | 6 shots |
| Drip coffee | 95 mg | 4 cups |
| Energy drink | 80 mg | 5 cans |
Caffeine is the world's most widely consumed psychoactive substance. Moderate consumption improves alertness, concentration, and athletic performance. Excessive intake causes anxiety, insomnia, heart palpitations, and digestive issues. The effects of caffeine are highly individual, influenced by genetics (particularly the CYP1A2 enzyme), body weight, tolerance, and health status.
Caffeine by Drink Type
Caffeine content varies widely even within the same drink category. A "coffee" from a light roast actually contains slightly more caffeine than a dark roast (contrary to popular belief — darker roasting destroys more caffeine). Cold brew is brewed with a higher coffee-to-water ratio and typically has significantly more caffeine than hot drip coffee. Espresso has more caffeine per milliliter than drip coffee, but less per serving because servings are smaller. Energy drinks vary from 80 mg (Red Bull) to over 200 mg per can for some brands.
Caffeine Sensitivity
Individual caffeine sensitivity varies dramatically. Genetic variation in the CYP1A2 enzyme — which metabolises about 95% of ingested caffeine — determines whether you are a "fast metaboliser" or "slow metaboliser." Fast metabolisers clear caffeine quickly and may tolerate higher amounts; slow metabolisers retain caffeine longer and are more prone to anxiety, sleep disruption, and cardiovascular effects even at lower doses. Coffee consumption before pregnancy and certain medications also affects sensitivity.
Frequently Asked Questions
How much caffeine is safe per day?
For healthy adults, the FDA recommends no more than 400 mg of caffeine per day — roughly 4 cups of drip coffee (95 mg each). Personalised by body weight, the safe threshold is approximately 5.7 mg per kilogram. A 60 kg person: 60 × 5.7 = 342 mg. A 90 kg person: 90 × 5.7 = 513 mg (capped at 400 mg for average sensitivity). Pregnant women: 200 mg/day maximum. Adolescents (12–18): 100 mg/day maximum. People with anxiety disorders, heart conditions, or on certain medications may have lower thresholds — consult a doctor.
How much caffeine is in a cup of coffee?
Caffeine content per cup depends on the brewing method and serving size. Average values: espresso (1 shot, 30 ml) = 63 mg; drip/filter coffee (240 ml) = 95 mg; instant coffee (240 ml) = 60 mg; cold brew (355 ml) = 155 mg; latte or cappuccino (355 ml) = 150 mg (made with 2 shots espresso); flat white (180 ml) = 130 mg; decaf (240 ml) = 3 mg. These are averages — actual content can vary ±20–30% based on bean variety, roast, grind size, and brew time.
What are the symptoms of too much caffeine?
Signs of caffeine overconsumption: restlessness and anxiety, rapid or irregular heartbeat, insomnia and difficulty falling asleep, headache, dizziness, tremors, upset stomach or acid reflux, increased urination, and irritability. Severe overconsumption (typically above 1,200 mg in a short period) can cause seizures and is potentially fatal. If you experience heart palpitations or severe anxiety after caffeine, reduce intake and consult a doctor. Note: 1,200 mg caffeine in powdered form is equivalent to a teaspoon — one reason pure caffeine powder is considered dangerous.
Does decaf coffee have any caffeine?
Yes — decaf coffee is not caffeine-free. FDA regulations allow decaf to contain up to 0.1% caffeine by weight. A typical 240 ml cup of decaf contains 2–15 mg of caffeine, with an average around 3 mg. This is far less than regular coffee (95 mg) but not zero. For people who are highly caffeine-sensitive or have been advised to eliminate caffeine completely (e.g., during pregnancy or with certain heart conditions), decaf should still be consumed cautiously and counted toward daily intake.