How long does caffeine last?

Caffeine peaks in your blood 30 to 60 minutes after you drink it, half of it is gone after about 5 hours, and a noticeable amount can stay in your system for 10 hours or more.

The curve after one cup

An 8 fl oz cup of brewed coffee has 95 mg of caffeine. Sipped over 15 minutes, it peaks about 1 hour after you start, at roughly 81 mg, because some is already being cleared while the rest is still being absorbed. Then it falls by half about every 5 hours.

Hours after you start	Still in you
1	80 mg
2	76 mg
3	67 mg
4	58 mg
6	44 mg
8	33 mg
10	25 mg
12	19 mg
16	11 mg
24	3.6 mg

How long until it stops affecting sleep

Time from starting the drink until the caffeine from it is below each line, for an average adult (5-hour half-life):

Drink	Under 100 mg	Under 50 mg	Under 25 mg
Espresso Single shot (1 fl oz), 63 mg	Never above it	2 hours	7 hours
Black Tea 8 fl oz cup, 47 mg	Never above it	Never above it	5 hours
Coca-Cola 12 fl oz can, 34 mg	Never above it	Never above it	2.5 hours
Red Bull 8.4 fl oz can, 80 mg	Never above it	4 hours	9 hours
Coffee 8 fl oz cup, 95 mg	Never above it	5 hours	10 hours
Starbucks Cold Brew Grande, 205 mg	5.5 hours	10.5 hours	15.5 hours
Starbucks Pike Place Roast Grande, 315 to 390 mg	9.5 hours	14.5 hours	19.5 hours

So a large coffee-shop coffee in the early afternoon can still be above 50 mg at midnight, while a cup of tea is below 25 mg within a few hours.

Feeling it versus having it

The alert, focused feeling usually fades two to four hours after a drink, as your body gets used to the level and it starts to fall. That is why it is easy to think caffeine has worn off by the evening. It has not: the caffeine is still blocking adenosine, and studies that measure sleep find lighter, shorter deep sleep from caffeine taken six hours before bed. Use the caffeine calculator for one drink, or the full check for your day.

FAQ

How long does it take for caffeine to wear off?

You stop feeling the boost after a few hours, but caffeine is still in your system much longer: about half is left after 5 hours and a quarter after 10 for an average adult.

How long does caffeine stay in your system?

It takes about five half-lives, roughly 25 hours, for caffeine to be essentially gone, though by 10 to 12 hours most drinks are below the level that affects sleep.

Look up a drink

Estimates, not medical advice. How it works.