Add up caffeine from coffee, tea, energy drinks, and other sources to see your daily total, percentage of safe limits, and estimated clearance time.
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Health — Nutrition
Caffeine is the most widely consumed psychoactive substance in the world, found in coffee, tea, energy drinks, soft drinks, chocolate, and medications. Tracking daily intake helps you stay within safe limits, time caffeine to avoid sleep disruption, and recognise when pregnancy or health conditions call for extra caution.
Health authorities including the FDA and EFSA set 400 mg per day as the upper level for healthy adults. Pregnant women and those trying to conceive should stay below 200 mg daily, as higher intake is associated with increased miscarriage risk and low birth weight. People with anxiety disorders, heart conditions, or high blood pressure may benefit from lower thresholds; consult your doctor if any of these apply.
A standard 240 mL (8 fl oz) drip coffee contains roughly 95 mg, an espresso shot around 63 mg, black tea about 47 mg, and green tea about 28 mg. Energy drinks typically provide 80 mg per 240 mL serving. A 355 mL can of cola contributes around 34 mg. Dark chocolate adds approximately 23 mg per 28 g square. Decaf coffee still contains a small amount — around 5 mg per cup.
Caffeine has a half-life of roughly five hours, meaning half the caffeine from a 3 pm coffee will still be active at 8 pm. For most adults, avoiding caffeine after 2–3 pm helps minimise sleep disruption. Age, liver function, certain medications (especially hormonal contraceptives), and pregnancy can all slow caffeine metabolism and extend its effects.
Frequently asked questions
Genetic variants in the CYP1A2 enzyme affect how quickly your liver processes caffeine. Slow metabolisers clear caffeine up to four times more slowly than fast metabolisers, making them more sensitive to the same dose. Pregnancy, oral contraceptives, and some antibiotics also slow metabolism significantly.
Yes. Regular caffeine use leads to adenosine receptor upregulation, meaning more receptors are available for caffeine to block. This reduces the stimulant effect over time. Many habitual coffee drinkers primarily drink coffee to reach a functional baseline rather than experiencing a noticeable boost.
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