How long it lasts, and how much is left at bedtime.
Caffeine leaves slowly. Half of what you drank is still there five hours later. Half of that five hours after. The coffee is finished long before the caffeine is.
A cappuccino at four in the afternoon
Call it 130 mg, about what a double shot carries. By 23:00, roughly 49 mg is still in you. That is most of a fresh espresso, at bedtime.
Work it out for your own coffee →
A daily total cannot tell you this. Two people can drink the same amount and go to bed in different states. What matters is when.
What common drinks carry
Reference figures, not a measurement of your cup. Beans, dose and grind all move the real number.
The published reference points
Population figures from EFSA and the FDA, for healthy adults. Not targets, and not advice for you.
Where the five hours is wrong
Between healthy adults it runs three to seven hours, mostly down to genetics. Longer in pregnancy and on the pill, shorter for smokers. Caffeine also takes half an hour to peak, so the first stretch here is overstated.
So every figure here is an estimate of an estimate. Enough to see the shape of a day. Not a measurement of you.
Your own curve, without the arithmetic
The app does this for every brew you log, and shows what is left at bedtime. On iPhone it writes to Apple Health, so tea counts too.
Get the app