Your drinks of the day and your bedtime. You see what is left in your blood when you go to sleep, against the published references. No advice, nothing is stored.
The tool adds up the caffeine of each drink using the average contents published by EFSA: 80 mg for an espresso, 90 mg for a drip coffee, 50 mg for a tea, 40 mg for a cola and 80 mg for an energy drink.
It then halves the amount every 5 hours, the average adult half-life, to draw how much is still there hour by hour and what is left at bedtime. It is a simple model: absorption is treated as immediate.
In adults it takes about 5 hours on average to clear half of the caffeine absorbed. This varies widely between people: genetics, smoking, pregnancy and some oral contraceptives change it.
In a controlled trial, 400 mg of caffeine taken six hours before bed cut sleep by more than an hour, measured at home. EFSA notes that doses around 100 mg close to bedtime can delay sleep onset in some adults.
For healthy adults, EFSA raises no safety concern up to 400 mg a day and up to 200 mg per intake. During pregnancy and breastfeeding its reference is 200 mg a day; under 18, about 3 mg per kilo per day.
On average: 80 mg in an espresso, 90 mg in a drip coffee, 50 mg in a cup of tea, 40 mg in a can of cola and 80 mg in a can of energy drink. Actual contents vary with preparation.
No. Everything is computed in your browser and nothing is sent to our servers. If you ask for it, your results can be kept on your device, in your summary, and deleted at any time.