When should you stop drinking coffee?

For an 11 pm bedtime, most people should finish an 8 fl oz cup of brewed coffee by about 5:50 pm, and earlier for bigger drinks or if caffeine keeps you up easily.

The short answer

An 8 fl oz cup of brewed coffee (95 mg) needs to be finished by about 5:50 pm for an average adult to be under 50 mg of caffeine at an 11 pm bedtime and through the night. The tables below work it out for other drinks, bedtimes and sensitivity levels.

These are latest start times for one drink on its own. If you have already had coffee earlier, some of it is still in you; the CaffeineIQ check adds up your whole day and gives a personal last call.

Latest time by drink, 11 pm bedtime

Drink	Very sensitive under 25 mg	Average under 50 mg	Not very sensitive under 100 mg
Espresso Single shot (1 fl oz), 63 mg	3:50 pm	8:50 pm	Any time
Black Tea 8 fl oz cup, 47 mg	5:55 pm	Any time	Any time
Coca-Cola 12 fl oz can, 34 mg	8:20 pm	Any time	Any time
Red Bull 8.4 fl oz can, 80 mg	2:05 pm	7:05 pm	Any time
Coffee 8 fl oz cup, 95 mg	12:50 pm	5:50 pm	Any time
Starbucks Cold Brew Grande, 205 mg	7:20 am	12:20 pm	5:20 pm
Starbucks Pike Place Roast Grande, 315 to 390 mg	Too much for one evening	8:25 am	1:25 pm

Latest time for a cup of coffee, by bedtime

Bedtime	Very sensitive	Average	Not very sensitive
9 pm	10:50 am	3:50 pm	Any time
10 pm	11:50 am	4:50 pm	Any time
11 pm	12:50 pm	5:50 pm	Any time
Midnight	1:50 pm	6:50 pm	Any time
1 am	2:50 pm	7:50 pm	Any time

"Very sensitive" assumes you notice 25 mg at bedtime; "not very sensitive" assumes 100 mg. If coffee after lunch keeps you up, you are probably in the first column.

Why the cut-off is so early

Caffeine blocks adenosine, the chemical that builds up during the day and makes you sleepy. Even when you fall asleep easily, caffeine still in your system makes deep sleep lighter and shorter, which is why an afternoon coffee can leave you tired the next day without ever feeling like it kept you up. With a 5-hour half-life, it takes 10 hours to get down to a quarter of what you drank.

FAQ

How many hours before bed should I stop drinking coffee?

For an 8 fl oz cup of brewed coffee, about 8 to 10 hours for most people. A large coffee-shop coffee can need 12 hours or more.

Is it OK to drink coffee at 3 pm?

One regular cup at 3 pm leaves about 30 to 40 mg at an 11 pm bedtime for an average adult, under the 50 mg most people sleep fine with. A large cold brew or drip coffee at 3 pm usually does not.

Look up a drink

Estimates, not medical advice. How it works.