Will this coffee keep me up?
Pick what you drank, when, and when you want to be asleep. The number below is what is left by then.
How the number is worked out
Half of what you drank is gone after five hours. Half of the rest five hours after that. A bedtime earlier on the clock counts as the next day.
The drink figures are reference values, not a measurement of your cup. Beans, dose and grind all move it.
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 an evening. Not a measurement of you.
The published reference points
Population figures from EFSA and the FDA, for healthy adults. Not targets, and not advice for you.
Every cup, not just this one
This page does one drink. The app does every brew you log, with nothing to type. On iPhone it writes to Apple Health, so tea counts too.
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