Your body

How fast caffeine peaks and clears differs from person to person. Set yours.

Half-life

Most healthy adults fall between 2 and 8 h, the shaded stretch, and the average is about 4 h. Pregnancy can stretch it toward 16 h.

Peak after a drink

Caffeine peaks 30 to 120 minutes after you drink it, not at the sip.

Today

Every drink on the chart, with what is in it.

Your drinks today, with caffeine, energy and macros
Drink	Time	Serving	Caffeine mg	Energy kcal	Protein g	Carbs g	Fat g	Source
Filter coffee	07:45	200 ml	80	2	0.2	0.0	<0.1	1
Double espresso	13:00	2 shots, 60 ml	127	5	0.1	1.0	0.1	2
Black tea	16:30	200 ml	40	2	0.0	0.6	0.0	3 4
Total			247	9	0.3	1.6	0.1

Total247 mg · 9 kcal

1USDA FoodData Central (SR Legacy): Beverages, coffee, brewed, prepared with tap water
2USDA FoodData Central (SR Legacy): Beverages, coffee, brewed, espresso, restaurant-prepared
3USDA FoodData Central (SR Legacy): Beverages, tea, black, brewed, prepared with tap water
4U.S. Food and Drug Administration: Spilling the Beans: How Much Caffeine is Too Much?

Worth knowing

4 his the average caffeine half-life for healthy adults. Most people fall between 2 and 8 hours.
30–120 minis how long caffeine takes to peak after you drink it, not the moment you sip.
100 mgnear bedtime can change sleep in some adults.

How fast does caffeine kick in?: Caffeine reaches its highest level in the blood 30 to 120 minutes after it is swallowed, not at the first sip.
How long does caffeine stay in you?: In healthy adults, caffeine's half-life, the time the body takes to eliminate half of it, averages about 4 hours, with a range of about 2 to 8 hours. It varies with factors such as age, body weight, pregnancy, medication and liver health.
How much caffeine is too much?: EFSA concludes that caffeine intakes up to 400 mg a day from all sources, spread through the day, do not raise safety concerns for healthy adults, except pregnant women. FDA cites 400 mg a day for most adults as an amount not generally associated with negative effects, and notes wide variation in how sensitive people are to caffeine and how fast they eliminate it.
Does caffeine in the afternoon affect sleep?: A single 100 mg dose of caffeine, about 1.4 mg/kg body weight for a 70 kg adult, may increase the time it takes to fall asleep and reduce sleep duration in some adults, particularly when taken close to bedtime.

How the curve is made

Resources

The long answers

What is in the cup, how long it stays, and what stopping does. The answer first, then the working, and every number links to where it came from.

All articles

Coffee

How much caffeine is in a cup of coffee?

An 8 fl oz cup of brewed coffee has about 95 mg of caffeine by USDA’s figure. A Starbucks cup the same size states 155 mg to 195 mg. Tables by size and type.

11 November 20268 min read