Nutrition & supplements
How much caffeine can you safely take per day?
Maximum daily caffeine and pre-workout dose based on body weight, with espresso equivalents.
Quick answer
Caffeine is the world’s most used performance enhancer — and one of the few backed by overwhelming evidence for both mental alertness and physical output. But the right amount is personal: it scales with body weight, which is exactly what this calculator does using EFSA’s safety thresholds (3 mg/kg per single dose, about 5.7 mg/kg per day, capped around 400 mg for healthy adults).
Safe daily maximum
400 mg
- Maximum single dose
- 225 mg
- Pre-workout (30-60 min before)
- 225 – 450 mg
- Espresso equivalent (~80 mg)
- 5 shots per day
EFSA limits: 3 mg/kg per single dose, 5.7 mg/kg per day (max ~400 mg for a healthy adult). During pregnancy the limit drops to 200 mg. Avoid caffeine 6-8 hours before sleep. Not a substitute for medical advice.
How it works
For context on real doses: an espresso carries roughly 80 mg, a filter coffee mug 90-140 mg, an energy drink 80-160 mg, and pre-workout supplements 150-300 mg per scoop — it adds up faster than most people think. For sports performance, research supports 3-6 mg/kg taken 30-60 minutes before training. And because caffeine’s half-life is 5-6 hours, that 4 PM coffee is still half in your blood at 10 PM: if sleep matters to you, front-load your intake in the morning.
The dose matters less than the hour you take it. Caffeine has a half-life of roughly five to six hours, so a coffee at four in the afternoon still has half its dose circulating at ten in the evening — and the sleep it costs takes back more performance than the caffeine gave. There is also a large genetic spread: some people clear it in about three hours, others take nine, which is why identical espressos leave one person unaffected and another awake. If you sleep badly and never suspected coffee, the test is a fortnight with nothing after midday.
Frequently asked questions
How much caffeine is in an espresso vs energy drinks?+
A single espresso has about 60-80 mg; a double, 120-160 mg. A standard 250 ml energy drink carries ~80 mg, but the 500 ml cans reach 160-200 mg. Filter and moka coffee sit at 90-140 mg per mug. Tea has 30-50 mg, cola about 35 mg, and dark chocolate adds 20-60 mg per 100 g.
When should I take caffeine before a workout?+
Blood levels peak 30-60 minutes after ingestion, so that’s the window to aim for. Research supports 3-6 mg/kg for strength and endurance benefits — for a 75 kg person, 225-450 mg, though regular coffee drinkers may need the higher end. If you train in the evening, weigh the performance boost against the sleep cost: sleep loss hurts progress more than caffeine helps.
Why doesn’t coffee affect me anymore?+
Tolerance: with regular intake, your brain grows more adenosine receptors to compensate, blunting the alerting effect within 1-2 weeks of steady use. The fix isn’t more caffeine — it’s a reset: 1-2 weeks at low or zero intake restores sensitivity. Expect 2-4 days of headaches and low energy when quitting; tapering gradually softens it.
Is 400 mg of caffeine a day really safe?+
For healthy adults, yes — that’s the ceiling EFSA and FDA agree on, roughly 4-5 espressos spread across the day. The limit drops to 200 mg/day during pregnancy, and people with heart arrhythmias, anxiety disorders or reflux should stay lower. Warning signs you’ve overshot: jitters, racing heart, anxiety and disturbed sleep. This is general information, not medical advice.
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